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Neuropsychological evaluations are used to examine a person’s current cognitive functioning. Performance validity tests (PVT) are included in neuropsychological test batteries to ensure that examinees are performing to the best of their abilities and identify non-credible performance. There are two types of PVTs: freestanding and embedded. A freestanding PVT is a cognitive test created to evaluate performance validity and do not measure any type of cognition directly. Meanwhile, an embedded PVT is a task design to evaluate some sort of cognition (e.g., memory) by using traditional neuropsychological tests (e.g., Trail Making Test) and performance validity. Research suggests that undergraduate college students are not always performing to the best of their abilities when completing a comprehensive neuropsychological battery. In fact, in one study where an undergraduate college sample was given three PVTs, it was reported that 56% of the participants failed at least one PVT in their first session and 31% in their second session. Research has also shown that speaking multiple languages can influence cognition. The purpose of this study was to identify in three credible language groups of college students what PVTs does bilingualism influence higher failure rates. It was predicted that bilingual college students would significantly demonstrate higher PVTs failure rates compared to monolingual college students.
Participants and Methods:
The sample consisted of 70 English first language monolinguals (EFLM), 33 English first language bilinguals (EFLB), and 68 English second language bilinguals (ESLB) that were psychologically and neurologically healthy. All participants completed a comprehensive neuropsychological battery in English. The Rey-Osterrith complex figure copy test, Comalli Stroop part A, B, and C, Trail Making Test part A and B, Symbol Digit Modalities Test written and oral parts, Controlled Oral Word Association Test (COWAT) letter fluency, and Finger Tapping Test were the tasks used as embedded PVTs to evaluate failure rates in our sample. Moreover, all participants were credible (i.e., they did not fail two or more PVTs). PVT cutoff scores were selected for each embedded PVT from previous literature. Chi-square analysis were used to evaluate failure rates between language groups on each PVT.
Results:
We found no significant failure rate differences between language groups on any of the PVTs. However, while no significant group differences were found, on the COWAT letter fluency results revealed higher failure rates between the three language groups (i.e., 13% EFLM, 24% EFLB, and 22% ESLB) compared to other PVTs.
Conclusions:
Our data suggested no significant failure rate differences between language groups. It has been suggested in previous studies that linguistic factors impact PVT performance and test interpretation. On the COWAT letter fluency task, it is possible that language is driving higher failure rates between bilingual speakers, even though we found no significant failure rates or performance differences between the three language groups. Future studies should examine language groups and other cultural variables (e.g., time perspective) to determine what may be driving high failure rates on the COWAT letter fluency task in credible participants.
The CCoSI is a brief screening instrument that is designed to detect cognitive impairment in children aged 5y0m-16y11m shortly after acquired brain injury (ABI) by evaluating language, fluency, attention, memory, and visuospatial domains. Each domain translates to a CCoSI index and is composed of a series of brief subtests. This study assessed the feasibility of modifying the Children’s Cognitive Screening Instrument (CCoSI) into an electronic version (eCCoSI) and administering it using video teleconferencing (VTC).
Participants and Methods:
Tasks and stimuli were modified for online administration. Typically developing children aged 5y0m-16y11 m were tested using the modified eCCoSI via VTC. The eCCoSI was administered using Skype for Business and Microsoft Teams. Participants attended one 25-minute video assessment session over either platform. Results of VTC-assessed healthy controls were compared to age-matched peers ([25] Female: [19] Male; mean age = [11.54], SD = [3.01], age range =5.00-15.75) who had been previously tested face-to-face (FTF) with the original CCoSI at the Bristol Royal Hospital for Children (BRHC).
Age-related trends in performance were also examined across FTF and VTC for comparability.
Results:
44 typically developing children were virtually assessed ([25] Female: [19] Male; mean age = [11.79], SD = [3.03], age range =5.05-16.92). Results from a 2x2 ANOVA with age-group and modality as independent factors showed no significant difference in performance between participants tested FTF and VTC over the CCoSI Attention, Fluency, Language, Memory, and Visuospatial indices. No significant result of interaction between age and modality was found; however, there was a significant result of age-group.
Conclusions:
VTC assessment is a feasible alternative to FTF administration of the CCoSI within healthy controls. Results from the present study are promising for the use of the eCCoSI in clinical practice. Further research should attempt to replicate these results within clinical populations.
Bilingualism has shown to have significant implications for neuropsychological assessment, namely, the Digit Span task. Moreover, bilingual individuals have been shown to exhibit both advantages and disadvantages on Digit Span; however, the relationship between bilingualism and performance on this subtest is poorly understood. This research aims to better understand how Hispanic Spanish-English bilinguals perform on this commonly administered working memory subtest.
Participants and Methods:
Participants included 82 Hispanic Spanish-English bilinguals [Age: M=29.11 (SD=6.369); Education: M=15.68 (SD=2.255); 53.7% female]. The participants completed the Language and Social Background Questionnaire (LSBQ; composite factor scores) and the Wechsler Adult Intelligence Scale -Fourth Edition (WAIS-IV) Digit Span (raw scores) subtest via Zoom, an online video conferencing platform. A hierarchical multiple regression analysis was utilized to predict participants’ Digit Span performance based on their LSBQ composite factor scores. Hierarchical multiple regression analyses were conducted using SPSS Version 27.
Results:
LSBQ composite factor scores significantly predicted Digit Span Forward, F (3, 78) = 1.835, p < 0.43 (R2 = .030) and Longest Digit Span Forward, F (1, 78) = 4.02, p < 0.48 (R2 = .041) scores. LSBQ composite factor scores did not significantly predict Digit Span Backward, F (3, 78) = .344, p = .941, Digit Span Sequencing, F (3, 78) = .598, p = .731, Digit Span Total, F (3, 78) = .440, p = 0.296, Longest Digit Span Backward, F (3, 78) = .510, p = .666, or Longest Digit Span sequencing F (3, 78) = .200, p = .751 scores.
Conclusions:
Results suggest that Hispanic Spanish-English bilinguals perform worse on Digit Span Forward and Longest Digit Span Forward as their bilingual experiences increase. However, bilingual experiences did not significantly predict Digit Span Backward, Digit Span Sequencing, Digit Span Total, Longest Digit Span Backward, or Longest Digit Span Sequencing scores. The contrasts in Digit Span performance may be attributed to the different ways in which each condition of the subtest is cognitively processed. Therefore, clinicians and researchers should use caution when interpreting test data for Digit Span with Hispanic Spanish-English bilinguals.
Typical evaluations of adult ADHD consist of behavior self-report rating scales, cognitive or intellectual functioning measures, and specific measures designed to measure attention. Boone (2009) suggested monitoring continuous effort is essential throughout psychological assessments. However, very few research studies have contributed to malingering literature on the ADHD population. Many studies have reported the adequate use of symptom validity tests, which assess effortful performance in ADHD evaluations (Jasinski et al., 2011; Sollman et al., 2010; Schneider et al., 2014). Because of the length of ADHD assessments, individuals are likely to become weary and tired, thus impacting their performance. This study investigates the eye movement strategies used by a clinical ADHD population, non-ADHD subjects, and malingering simulators when playing a common simple visual search task.
Participants and Methods:
A total of 153 college students participated in this study. To be placed in the ADHD group, a participant must endorse four or more symptoms on the ASRS (N = 37). To be placed in the non-ADHD, participants should have endorsed no ADHD symptoms (N = 43). Participants that did not meet the above criteria for ADHD and not-ADHD were placed in an Indeterminate group and were not included in the analysis. A total of 20 participants were instructed to fake symptoms related to ADHD during the session. A total of twelve Spot the Difference images were used as the visual picture stimuli. Sticky by Tobii Pro (2020) was used for the collection of eye-movement data was utilized. Sticky by Tobii Pro is an online self-service platform that combines online survey questions with an eye-tracking webcam, allowing participants to see images from their home computers.
Results:
Results indicated on the participants classified as Malingering had a significantly Visit Count (M = 17.16; SD= 4.99) compared to the ADHD(M = 12.53; SD= 43.92) and not-ADHD groups (M =11.51; SD=3.23). Results also indicated a statistically significant Area Under the Curve (AUC) = .784; SE = .067; p -.003; 95% CI = .652-.916. Optimal cutoffs suggest a Sensitivity of 50% with a False Positive Rate of 10%.
Conclusions:
Results indicated that eye-tracking technology could help differentiate simulator malingerers from non-malingerers with ADHD. Eye-tracking research’ relates to a patchwork of fields more diverse than the study of perceptual systems. Due to their close relation to attentional mechanisms, the study’s results can provide an insight into cognitive processes related to malingering performance.
Youth athletes with concussion are at an increased risk of sustaining new concussions and orthopedic injuries after clearance for return-to-play. There are training programs, extensively studied in other patient populations, which can improve performance in cognitive domains that have been implicated in sport-related injury and re-injury after concussion (i.e., visual attention/processing speed). The Useful Field of View (UFOV) is one such training program, accompanied by a computerized adaptive assessment for evaluating response to training and maintenance in clinical trials. Remote UFOV assessment administration may help improve adherence, particularly in assessing long-term training effects. The current study explores the feasibility of virtual UFOV assessment and equivalence with in-person administration in youth clinically recovered from concussion and healthy controls.
Participants and Methods:
Participants included youth ages 10-18 enrolled in a longitudinal study examining neural recovery following medical clearance from concussion. UFOV was attempted in 61 participants (Mage=15.06; SD=2.00; n=19 in-person; n=42). Of these, 7 virtual administrations were discontinued due to computer limitations, and 1 in-person administration was excluded due to overall performance validity concerns. This resulted in a total sample of 53 participants (Mage=15.02, SD=2.00, 58.5% male; n=14 concussion, Mdays_since_injury=272.64, SD=185.35; n=39 controls). UFOV was administered either in-person (n=18) using manual guidelines or virtually (n=35) on the participant’s computer using video-conference screen-share and a secondary device for an additional view of the participant and their keyboard/mouse. For virtual visits, the examiner recorded concerns about the remote testing environment (e.g., screen glare, viewing distance not measured appropriately), and analyses were conducted with and without cases with concerns. Between-group (in-person vs virtual administration) demographic differences were examined using chi-square tests/t-tests. Mann-Whitney U tests were used to examine for differences in UFOV scores (ms; higher scores are worse) by administration context (in-person vs. virtual) given threats to normality.
Results:
For virtual administrations, the most commonly reported concerns about the remote testing environment were related to lighting (n=12) and viewing distance (n=3). There were no significant differences in age, sex, concussion history, sport participation history, or IQ by administration context (in-person vs. virtual). UFOV performance did not vary significantly by administration context for processing speed or divided attention subtests, but performance on the selective attention subtest was significantly better in the virtual administration group (Median in-person =93.33; Medianvirtual=63.33; U=203.00, p=0.035). This trend persisted after removing an outlier (>2SD; p=0.065) and after removing cases where lighting (p=0.060) and screen-viewing distance (p=0.085) were not adequately controlled.
Conclusions:
Though preliminary, results suggest that UFOV can be administered virtually, in youth with and without a history of concussion, but that those assessed virtually using their home computer may have an advantage, particularly for the selective attention subtest. This may be due to comfort level within the home environment or subtle differences in viewing distance that were not appreciated by the examiner remotely. Importantly, not all participants were able to complete the assessment virtually due to computer limitations. Future work with larger samples size should examine the extent to which completers vary from non-completers in terms of sociodemographic variables.
Behavior is the product of interconnected brain regions that work together as networks. This case study examines whether there are differences between a participant with a large congenital left temporal lobe cyst, which impacted the volume of structures in the region, and control subjects of similar age on cognitive tasks and network connectivity as measured by resting-state functional magnetic resonance imaging (rs-fMRI).
Participants and Methods:
The case participant (CP; 71 year old female) and controls (CON; n = 25; 48% female) were recruited as part of a larger aging study. CON were chosen from the larger study population by age (+/- 10 years from CP; Range = 68-86 years). Cognitive tasks included: Shopping list memory task, Montreal Cognitive Assessment, WAIS-IV subtests: Digit Span, Digit-Symbol, Symbol Span, and Letter-Number Sequencing. For rs-fMRI, we administered four blood-oxygen level dependent (BOLD) functional connectivity (rs-fMRI) scans at 6 minutes each. Image processing was conducted using the CONN toolbox. Independent sample t-tests evaluated differences between CP and CON. Segregation was evaluated in the Auditory (Au), Cerebellar-basal ganglia (CBBG), Cingulo-Opercular Task Control (COTC), Dorsal Attention (DA), Default Mode (DMN), Fronto-Parietal Task Control (FPTC), Salience (Sa), Sensory Somatomotor Hand (SSH), Sensory Somatomotor Mouth (SSM), Visual (Vi), and Ventral Attention (VA) networks to assess CP’s functional segregation by network throughout the brain. Bonferroni correction was applied to account for multiple comparisons in cognitive testing (.05/7 for significance at p < 0.007) and network segregation (.05/11 for significance at p < .005).
Results:
Independent samples t-tests did not reveal significant differences across cognitive tasks (t(24) <1.04, p > .05). Network segregation did not reveal significant differences between CP and CON across networks examined (t(24) < 1.269, p > .005). However, DMN and DA segregation trended toward significance (t(24) = -2.724, p = .006 and t(24) =-2.006, p = .028), respectively) with CP demonstrating lower segregation as compared to CON.
Conclusions:
CP performed similarly on cognitive testing to CON, indicating that the congenital presence of a large temporal lobe cyst did not impact global cognition, list learning and memory, working memory, or processing speed. CP did not demonstrate significantly different segregation across networks of interest after Bonferroni correction. Our cognitive performance results are consistent with a similar case-study examining language, which revealed intact linguistic abilities (Tuckete et al., 2022). The lack of differences in cognitive performance and segregation highlight the capacity for plasticity in the human brain, even in the presence of a large structural abnormality. This also suggests that the processes of aging in this case are not markedly different from controls. In future research we intend to expand on this case study by evaluating right temporal to hippocampal seeds and language network seeds to delve deeper into memory and language functioning.
Theory suggests that symptoms of Attention-deficit Hyperactivity Disorder (ADHD; e.g., hyperactivity and impulsivity) may be associated with social cognition deficits characterised by fast but erroneous processing of social cues. Despite this, prior research has provided mixed evidence for (a) deficits in social cognition skills and (b) a link between such deficits and poor social outcomes among children with ADHD. We sought to clarify this ambiguity by (a) exploring variation in social cognition skills across a mixed clinical and normative population and (b) examining the demographic, clinical, and dimensional symptom profiles of children presenting with reduced social cognition skills characterised by fast but erroneous processing.
Participants and Methods:
Participants were children and adolescents (N = 1,097) aged 4–18 years (M = 9.02, SD = 2.72) assessed using the Paediatric Evaluation of Emotions Relationships and Socialisation (PEERS), a child-direct, ecologically sensitive measure of social cognition. Latent profile analysis of standardised social cognition scores and response times for incorrect encoding of social cues (error-response times) was used to identify social cognition profiles. Differences between each profile in terms of demographics, clinical profiles, symptom dimensions, and social outcomes were explored.
Results:
Four social cognition profiles were identified. Two profiles were identified as being of particular interest: one which captured typically developing children (TDC; n = 727), and another which was characterised by lower social cognition scores and faster error-response times (impulsive responding; n = 201). The remaining profiles captured the response styles of younger participants (n = 152) and children with more pervasive social cognition deficits (n = 17). Comparison of the two profiles of interest revealed a number of statistically significant differences (p < .05). Compared to the TDC group, the impulsive responding group had: higher SDQ scores for hyperactivity, conduct, emotional, and peer problems; lower IQ and prosocial scores, and; greater parent-perceived social function deficits. Children in this group were also more likely to be male and from a lower SES background. Clinically, 18% of children in the impulsive responding group had an ADHD diagnosis, and 14% had at lease one mental health diagnosis other than ADHD.
Conclusions:
A large minority of children (~18%) demonstrate social cognition deficits characterised by fast but erroneous processing of social cues. Although the explorative nature of this study does not allow conclusions to be made about the causes of such deficits, it is reasonable to conclude that they are not reducible to clinically significant symptoms of hyperactivity-impulsivity — less than 1/5 of the children in this group had an ADHD diagnosis, and 2/3 of children in this group had no mental health diagnosis at all. Child-direct tools designed to detect individual differences in social cognition skills may be beneficial in identifying individuals who will benefit from social support or interventions aimed at reducing social cognition deficits despite being missed by more traditional screening measures (e.g., clinical diagnoses). Future work should focus on understanding the causal relationships between symptoms of hyperactivity-impulsivity, fast but erroneous processing of social cues, social cognition skills, and social outcomes for this group of children.
Although studies have shown unique variance contributions from performance invalidity, it is difficult to interpret the meaning of cognitive data in the setting of failed performance validity tests (PVT). Furthermore, a clearer understanding of the clinical utility of cognitive data in the context of invalid PVTs is necessary to inform decisions about battery length once PVTs are failed. The primary aim of the current study is to broadly describe cognitive outcomes in the setting of PVT failure.
Participants and Methods:
Two hundred and twenty-two veterans with a history of mild traumatic brain injury referred for clinical evaluation completed cognitive and performance validity measures. Standardized scores were characterized as Within Normal Limits and Below Normal Limits at the normative 16th percentile and number of Within Normal Limits scores were calculated for each participant. Cognitive outcomes are described across four commonly used PVTs. Rates of below normal limits cognitive performance, and PVT failure were assessed via student’s t tests among participants who were classified as productive or unproductive based on involvement in work and/or school.
Results:
Among participants who performed in the invalid range on TOMM trial 1, 36-81% of cognitive data reflected within normal limits performance. Similarly, 47-81% of those who demonstrated performance invalidity based on the Word Memory Test (WMT) earned broadly within normal limits scores across cognitive testing. For those with invalid performance based on the normative digit span scaled score, 35-88% of cognitive data was at or above the 16th percentile. Within normal limits across cognitive tests ranged from 16-71% when the California Verbal Learning Test-Second Edition forced choice was used as an indicator of performance validity. In the context of PVT failure, the average number of cognitive performances below the 16th percentile ranged from 5-7 of 14 tasks depending on which PVT measure was applied. Within the total sample, there were no differences in the total number of below normal limits performances on cognitive measures between productive and unproductive participants (T = 1.65, p = 1.00). Additionally, there were no differences in the total number of PVTs failed between the productive and unproductive groups (T = 0.33, p = 0.743).
Conclusions:
Results of the current study suggest that the range of within normal limits cognitive performance in the context of failed performance validity measures varies greatly. Importantly, findings indicate that neurocognitive data may still provide important practical information regarding cognitive abilities (i.e., that test takers can oftentimes perform within broadly normal limits on many cognitive tasks), despite poor PVT outcomes. Further, given that neither rates of below normal limits cognitive performance nor rates of PVT failures differed among productivity groups, results have important implications for decisions to continue testing and recommendations in a clinical setting.
Research has indicated that racial and ethnic minoritized groups in the United States are disproportionately affected by dementia (e.g., Alzheimer’s disease), and seek help (HS) later in the disease course, if at all. It has also been posited that individuals from different ethno-racial groups have divergent perceptions of the aging process, which may influence HS. These disparities warrant tailored preventive efforts to encourage identification of factors which contribute to HS to enable earlier psychoeducation and enhanced access to resources. The factors which influence HS may differ across ethnoracial groups. Here we examine the relative influence of subjective cognitive decline (SCD), a risk factor for AD, and aging perceptions to HS in these groups.
Participants and Methods:
The current sample consisted of 161 healthy older adults (51 Male, 110 Female), aged 51 to 92 (M=73.43, SD=6.85) with a mean education of 16 years (SD=2.3 years) who performed > -1.5 SD on clinical neuropsychological testing. 26.7% of the sample self-reported as race/ethnic minorities (e.g., Hispanic or Non-Hispanic African American, Asian, Other.) Participants completed a 20-item SCD questionnaire assessing perceived cognitive difficulties in comparison to same aged peers, in addition to measures assessing HS behavior, (e.g., Have you gone to the doctor specifically for memory concerns?), and aging perceptions (e.g., older adulthood group identification, explicit stereotypes, essentialism). Point biserial correlations examined relationships between SCD, HS and aging perceptions, and multinomial logistic regressions examined the contribution of SCD and aging perceptions to HS across majority (White) and minoritized groups (Non-White participants).
Results:
In bivariate analyses of the White participant group, HS was associated with SCD (r=0.43, p<0.001) and age group identification (r=0.27, p<0.01), and the latter were also associated (r=-0.19, p<0.05). The logistic regression model correctly classified 86% of participants (same as null), explaining a relatively small proportion of variance in HS, Snell R2 = 0.09, Nagelkerke’s R2 = 0.16. Age group identification was not associated with HS (b=-0.02, SE=0.26, p=0.94, 95% CI [0.59, 1.63] but SCD was (p=0.04). In the non-White group (n=42), bivariate analyses showed that HS was associated with essentialism (r=-0.41, p<0.01; belief aging as a fixed and inevitable process)) and explicit stereotypes (r=-0.42, p<0.01) but not with SCD (r=0.21, p=0.19). SCD was also associated with essentialism (p=-0.32, p<0.05), stereotypes (p=0.32, p<0.05), and age group identification (r=0.38, p<0.01). The regression model correctly classified 88.9% of participants (same as null); neither SCD (p=0.39), explicit stereotypes (p=0.43), essentialism (p=0.72), nor age group identification (p=0.62) contributed to HS when all were considered.
Conclusions:
When both SCD and age perceptions are examined together as predictors of HS, SCD alone predicts HS in the majority group. Neither construct predicts HS in the minoritized group—despite significant bivariate associations between HS, aging perceptions and SCD that varied across ethno-racial groups. Findings illustrate that SCD and aging perceptions may contribute differently to HS across ethno-racial groups in the US, and as such may indicate different priorities when implementing HS tools (e.g., screeners for detection of cognitive impairment). Ongoing work is addressing illness perceptions, another key barrier in HS in these groups to further inform on tailoring of services.
The Montreal Cognitive Assessment (MOCA) is a brief cognitive screener, widely used by providers to detect mild cognitive impairment (MCI). It encompasses 30 questions, assessing executive functioning, visuospatial skills, language, memory, attention, and orientation. Although the MOCA has been shown to have high sensitivity (90%) and specificity (87%) for detecting MCI, existing studies have primarily included participants who were already diagnosed with amnestic MCI via neuropsychological testing. Since several factors beyond the presence of MCI can contribute to low performance on the MOCA (e.g., premorbid IQ, fatigue, mood symptoms), over-reliance on the MOCA runs the risk of falsely identifying individuals as having cognitive impairment. The MOCA’s memory subtest raises particular concern as there are several language-based tasks between the learning and delay trials, introducing the potential for interference effects. Thus, the MOCA’s ability to accurately identify those at risk for MCI in the community remains unclear. The objective of the present study was to evaluate: (1) the MOCA’s association with neuropsychological memory measures; and (2) its ability to distinguish between neurocognitive groups (intact vs. MCI vs. dementia).
Participants and Methods:
This study involved a retrospective analysis of fifty-one patients (M age=72.58 [7.90]; M education= 16.37 [16.37]) who underwent neuropsychological evaluation. Standardized scores for total list-learning (HVLT; CVLT-bf) were used to capture memory encoding; retention % scores were used to capture memory storage. MOCA scores included Total MOCA, MOCA-Orientation, and the MOCA Memory Index (MOCA-MEM). MOCA-MEM was calculated based on Julayanont et al., 2014— (Free-Delayed Recall*3) + (Category-Cued Recall*2) + Multiple Choice-Cued Recall. Bivariate correlations were conducted for the MOCA and neuropsychological test scores. Participants were divided into three diagnostic groups, classified by the neuropsychologist: (1) Cognitive Intact (CI; n=13); (2) MCI (n=26); and (3) Major Neurocognitive Disorder/Dementia (MNCD; n=11). Analysis of covariance was used to analyze differences between the cognitive groups on Total MOCA, MOCA-Orientation, and MOCA-MEM.
Results:
Total MOCA correlated with word-list learning (r=.434, p=.004) and retention% (r=.306, p=.049). MOCA-MEM was correlated with word-list learning (r=.367, p=.042); it did not significantly correlate with retention%. MOCA-Orientation had the strongest correlation with retention0/) (r=.406, p=.009). Means of Total MOCA significantly differed between CI (25.31[2.56]), MCI (22.04[4.14]), and MNCD (15.44[4.13]). MOCA-MEM only differentiated CI (10[3.66]) and MNCD (5.71[2.14]); it did not differentiate MCI (6.94[3.13]) from either CI or MNCD.
Conclusions:
Our findings suggest that the MOCA has limitations in accurately classifying memory deficits in older adults. First, our study suggests that the MOCA-MEM reflects encoding rather than memory storage. Given that deficiency in encoding may be secondary to other cognitive deficits, such as attention and executive dysfunction, performance on MOCA-MEM cannot readily delineate the presence of an amnestic process. Second, the findings show that MOCA-MEM does not differentiate between patient groups with intact cognition versus MCI, nor those with MCI versus MNCD. These findings argue the importance of neuropsychological evaluation in deciphering patterns of memory performance and the presence of an amnestic process.
Some RCFT indices are effective Performance Validity Test (PVTs) during neuropsychological evaluations. A combination score that includes the copy score, true positive recognition, and atypical errors has proven to be especially useful (see Lu et al, 2003). However, this score was derived from administration that deviated from protocols outlined by Meyers & Meyers (1995) in that the Recognition trial was administered after the 3-minute delay instead of the 30-minute delay. The current study examined the utility of the RCFT combination score as a performance validity test (PVT) when completing the recognition trial after the 30-minute delay.
Participants and Methods:
This study utilized archival data from 298 Veterans who presented for a clinical neuropsychological evaluation at a southern Veterans Affairs Medical Center. The evaluation included up to nine PVTs and all trials of the RCFT (per Meyers & Meyers, 1995). Patients were considered credible if all PVT performance fell within normal limits. This resulted in 232 patients in the credible group (Mage = 52.9 years, SDage = 15.2, Medu = SDedu = 2.5, 88% male, 71.2% White, 28.3% Black/African American). Patients were considered non-credible if they failed >2 PVTs. This resulted in 66 patients in the non-credible group (Mage = 51.6, SDage = 13.79, Medu = SDedu = 2.4, 92.4% male, 56.1% White, 43.9% Black/African American). Group assignment was also clinically confirmed. Receiver operating characteristic (ROC) curve analyses were conducted to discriminate between credible and non-credible groups utilizing the established RCFT combination score.
Results:
RCFT combination scores distinguished groups, with credible participants scoring higher than non-credible participants (F[1, 296]=63.76, p<.001, d=1.11; M = 56.9, SD = 9.3 vs. M = 46.5, SD = 9.5, respectively). A ROC analysis indicated AUC = .800 (95% CI = .73 to .86). When specificity was set at >90%, a cut-score of <46.5 yielded sensitivity at 46.0%. The analogous cut-score from the Lu et al. (2003) study (i.e., <47) was associated with a specificity of 88.7 and sensitivity of 46.0% in the current study.
Conclusions:
As the Lu et al. (2003) established the combination score of the RCFT with procedures that deviated from the standardized protocol outlined by Meyers and Meyers (1995), clinicians who opted to adhere to Meyers and Meyers’ full protocol may have concerns about using the combination score as a PVT. The current study established a similar cut-off score to what Lu et al., (2003) reported (i.e., <46.5 vs. <47) while following a different administration procedure of the RCFT. Also, the index was moderately sensitive in the current study (i.e., 45.5%) but less so than what Lu et al. reported when using a cut-score that had >90% specificity (i.e., 75.9% sensitivity). This suggests that the index may be robust to deviations in administration procedures. Difference in sensitivity could be related to difference between samples. As the current sample was derived from a clinical, VA setting, current findings extend the generalizability of the index. Future research would benefit exploring if any subgroups would benefit from adjusted cut-scores to reduce the risk of false positive identification.
Cognitive flexibility, typically measured using neuropsychological tasks of set-shifting, has been associated with mental and physical health, social relationships, resilience, and overall quality of life (Diamond, 2013; Chen et al., 2014; Davis et al., 2010; de Abreu et al., 2014; Genet et al., 2011). Previous research has found conflicting results regarding the relationship between set-shifting and various measures of functional outcomes in individuals with traumatic brain injury (Allanson et al., 2017). The present study examined the relationship between cognitive flexibility and adaptive functioning in individuals with acquired brain injuries (ABI).
Participants and Methods:
Participants in this research are adults (n = 116) with severe, chronic ABI who completed a neuropsychological evaluation through Bancroft Neurorehab between 2012-2022. Participants ranged in age from 20.4 - 67.8 years (M = 45.8). Individuals included in data analysis completed Trails A and B, Wide Range Achievement Test, Fourth Edition (WRAT-4) Word Reading, and Texas Functional Living Scale (TFLS). Set-shifting ability was measured using Trails B and adaptive functioning was measured using the TFLS. Word reading ability, measured using the WRAT-4, was included as a covariate to account for the impact of word reading difficulties on Trails B performance.
Results:
A simple linear regression was conducted to examine if Trails B T-score (M = 24.7) and WRAT-4 Word Reading Standard Score (M = 87.8) predicted TFLS Total T-score (M = 35.8). The overall regression model was statistically significant (R2 = .351, F(2, 113) = 32.0, p < .001). It was found that lower performances on Trails B (ß = .272, p <.001) and WRAT-4 Word Reading (ß = .189, p <.001) both significantly predicted a lower TFLS Total T-score.
Conclusions:
Set-shifting and word reading ability significantly predicted the overall adaptive functioning score on the TFLS which adds to a body of literature that suggests that the ability to think and behave flexibly affects functional aspects of everyday living. These findings are consistent with previous literature regarding the association between cognitive flexibility and adaptive functioning in the general population, and these results add to the growing body of research on cognitive flexibility in individuals with brain injury. Clinicians may use an individual’s set-shifting performance to estimate and further assess potential difficulties in completing activities of daily living. This information may assist in subsequent treatment planning and identifying treatment goals of cognitive rehabilitation consistent with rehabilitation psychology’s goals of increasing levels of adaptive functioning and quality of life (Division 22 of the American Psychological Association, n.d.). Future research may examine if certain domains of adaptive functioning are more or less affected by impairments in cognitive flexibility. Future research may also examine patterns of set-shifting performance, such as sequencing errors vs. set-loss errors, associated with specific areas of insult.
Although relationships between Fried frailty criteria (i.e., weakness, slowness, weight loss, exhaustion and low physical activity), cognitive decline, and adverse childhood experiences (ACEs) have been examined (Brigalo et al., 2015, Brown et al., 2022, Fabricio et al., 2020, & Tani et al., 2021), the moderating effect of age on the relationship between ACEs and frailty has yet to be explored. The present study examined whether age moderates the relationship between total number of ACEs and number of frailty criteria in older age.
Participants and Methods:
137 older adults were recruited from University of Miami clinics and surrounding community care centers. Collected data included demographic information, number of frailty criteria met, and number of ACEs endorsed. Participants were primarily Hispanic-White (64.2%) and female (56.9%), with a mean age of 73.62 years (SD=6.252). Data were initially analyzed using descriptive statistics. A hierarchical linear regression was run to test the effect of ACE score on number of frailty criteria met. A simple moderation analysis using the PROCESS macro was then performed with total number of medical conditions included as a covariate to address any potentially confounding effects. To avoid multicollinearity issues, number of ACEs endorsed and age were mean centered and an interaction term between the two was produced.
Results:
Scores on the ACE did substantially effect the total number of frailty criteria met by participants in this study (f=2.37, p=0.028, ΔR2=0.023), independent of number of medical conditions. The overall moderation model was significant (f=2.99, p=0.022, R2=0.103), and the addition of the interaction effect resulted in a statistically significant change to the model (f=4.08, p=0.045, ΔR2=0.035). Taken together, support for a moderating effect was found, specifically within the lower age group (65 - 71years), but not older (greater than 72 years) with ACE score positively predicting the number of frailty criteria met (b =0.230, t=2.62, p=0.010).
Conclusions:
Results largely support the positive effect of ACE endorsement on the number of frailty criteria met in later life. Age acted as a moderating effect, for the younger old population, such that as number of ACEs endorsed increased, so too did the number of frailty criteria met. This finding highlights the importance of early intervention among those in younger late life who have experienced trauma. Given the positive relationship between frailty and cognitive decline in late life (Brigalo et al., 2015 & Fabricio et al., 2020), these findings also support the need for a better understanding of how childhood adversity impacts physical well-being over the life course.
Pediatric brain tumor survivors treated with proton radiation therapy (PRT) prior to 4 years of age are at high risk for poor cognitive and developmental outcomes. This cross-sectional study examined developmental outcomes and educational service utilization at follow-up in a cohort of pediatric survivors treated with PRT before the age of 4 years.
Participants and Methods:
A total of 46 patients (58.7% female, 93.5% White) were assessed using age-appropriate measures for executive, behavioral, and adaptive functioning. Mean age at PRT was 2.4 years (SD=0.9, range 1.0-3.9 years); mean age at follow-up was 7.0 years (SD=4.8, range 2.0-18.6 years). Mean follow-up interval was 4.57 years (SD=4.52, range 0.9-16.2 years). Diagnoses included ependymoma (n=26, 54.2%), medulloblastoma (n=7, 14.6%), craniopharyngioma (n=4, 8.3%), and a few other tumor types. Infratentorial tumors were most common (69.6%). Treatment included prior surgical resection (93.5%) and chemotherapy (60.9%). Posterior fossa syndrome was present in 10.9% (n=5). PRT field consisted of focal (n=41, 89.1%) or craniospinal irradiation (CSI) (n=5, 10.9%). The impact of demographic, diagnostic, and treatment-related factors was examined, including age at PRT, gender, time interval since PRT, radiation field, and tumor location, on intelligence quotient (IQ), adaptive skills, and executive functioning. Rates of impairment (T-scores >65) were calculated. The utilization of educational services was determined.
Results:
Mean IQ (SS = 97.6, SD=16.3), as well as mean global executive functioning (Mean T=53.4, SD=11.1) and adaptive skills (Mean SS = 92.5, SD=21.4), as assessed by parent rating scales (BRIEF; SIB), were in the average range. Despite mean scores being within the average range, a large proportion of patients demonstrated difficulties with social withdrawal (28.3%) and activities of daily living (28.3%) (BASC), and global executive dysfunction (17.4%) (BRIEF). Younger age at PRT was associated with lower global adaptive skills at follow-up (r=.39, p=.005), better activities of daily living (r=.53, p<.001), lower social skills (r=.43, p=.002), and more hyperactivity (r=-.37, p=.008), but not aggression, anxiety, depression, somatization, atypical behaviors, withdrawal, or attention problems. Longer follow-up interval was correlated with better activities of daily living (r=.46, p<.001), but more anxiety (r=.39, p=.006). Gender, SES, radiation field, history of hydrocephalus, and location of tumor were not significantly related to primary outcome variables. Posterior fossa syndrome was associated with lower adaptive skills (t=2.90, p=.003) and IQ (t=2.02, p=.026). Of those enrolled in school, 59% received special education services and/or accommodations (IEP n=18, Early Intervention n=6; 504 Plan n=3).
Conclusions:
Overall, PRT before age 4 years was associated with difficulties with withdrawal, adaptive skills, and executive functioning. Younger age at PRT was associated with lower adaptive functioning, lower social skills, and higher hyperactivity, but not with IQ, attention, mood, or anxiety. While a longer time interval since treatment was associated with improvement in activities of daily living, anxiety was increased, suggesting some late emotional effects. Furthermore, posterior fossa syndrome after surgery was related to lower adaptive skills and IQ. Attention problems were not indicated. Approximately half received school services/accommodations. Young children treated with PRT require proactive support and services to foster their developmental outcomes.
All premenopausal women who survive traumatic brain injury (TBI) will eventually experience menopause. Challenges experienced by women with TBI are superimposed on challenges associated with hormonal changes in midlife. Some women with stressful life contexts such as TBI are more vulnerable to the added burdens of the menopause transition, potentiating its effects. Although it may be argued that TBI research correctly overrepresents the male experience given disparities in injury rates (4:1), there are important differences in how females and males age, their specific health needs, and the psychosocial context of midlife. Development of evidence-based interventions begins with understanding the experience of menopause after TBI, including where and when key problems may emerge.
Participants and Methods:
All participants were women 40-60 years old, not taking hormones (i.e., replacement therapy or other systematic hormones), with intact ovaries. Women with TBI were > 2 years post injury, whose menstrual period returned after injury, and were living in the community. Severity of injury ranged from complicated-mild to severe TBI. Pre/peri and postmenopausal status was determined by presence/absence of menstrual period in previous 6 months, respectively. Eighteen common menopause symptoms (vasomotor, somatic, psychological, and cognitive) were assessed for presence and frequency (rarely-always), along with Quality of Life in Neurological Disorders (Neuro-QOL) Sleep Disturbance and Traumatic Brain Injury Quality of Life (TBIQOL) Anxiety, Depression, and Fatigue scales.
Results:
Overall, women with TBI (n = 68) showed greater presence and frequency of symptoms than women without TBI (n = 153), with fewer within-group differences by menopausal status. Among pre/peri-menopausal women, TBI and non-TBI groups did not significantly differ and showed small effect sizes on symptoms associated with changes in estrogen during menopause, including hot flashes, night sweats, bowel and bladder sequelae, and breast tenderness. However, pre/peri-menopausal women with TBI also endorsed body aches and headaches, as well as troubles with memory, focus, fatigue, cognitive concerns, sleep, and anxiety significantly more than their pre/peri-menopausal counterparts (all medium effect sizes). Among postmenopausal women, those with TBI had significantly greater frequency of hot flashes, crying spells, poor memory, worry, moodiness, panic attacks, sleep disturbance, and anxiety than women without TBI. Within TBI, only hot flashes and breast tenderness were greater in postmenopausal versus pre/peri-menopausal women. Within non-TBI, postmenopausal status was associated with significantly greater hot flashes, night sweats, restlessness, poor memory, irritability, sleep disturbance, and anxiety, with greater fatigue but not significantly.
Conclusions:
The findings support a model of TBI and menopause in which symptoms most closely associated with estrogen decline in pre/peri-menopause are generally similar between women with and without TBI, and symptoms that overlap with common TBI sequelae were generally more often present and frequently experienced among women with TBI versus non-TBI. We did not observe a synergistic or potentiating effect of TBI on menopause symptoms in post-menopause. These findings offer insight that contextualizes the experience of menopause symptoms among women with TBI. Such insights are essential for the development of treatment approaches that maximize health and wellbeing during the menopause transition for women with TBI.
Multiple Sclerosis (MS) affects up to 500,000 adults in the United States, with cognitive impairment present in 45%-65% of people. Studies showed hippocampal atrophy in MS, but the underlying mechanisms remain unknown. Inflammation has been proposed to play a significant role, and associations between systemic inflammatory biomarkers and hippocampal atrophy have been shown in other neurological conditions. However, research exploring serum biomarker and volumetric associations in MS are lacking. Given that conventional imaging methods lack resolution for hippocampal internal architecture (HIA), new protocols were developed. We used the High-Resolution Multiple Image Co-Registration and Averaging (HR-MICRA) method to visualize the HIA subfields. We investigated the relationship between subfield volumes generated from HR-MICRA scans and systemic serum biomarkers in MS.
Participants and Methods:
Patients with MS were recruited (N= 34, mean age= 54.6, 35.3% Black) underwent Magnetic Resonance Imaging (MRI), and serum biomarkers were obtained, specifically chosen for their potential role in MS. Inflammatory biomarkers included; granulocyte colony stimulating factor (G-CSF), interleukin-10 (IL-10), matrix metalloproteinase-9 (MMP-9), tumor necrosis factor- a (TNF- a), and growth factors; vascular endothelial growth factor (VEGF); insulin-like growth factor-1 (IGF-1), and brain derived growth factor (BDNF). Imaging was performed in a Siemens Prisma 3T scanner with a 64-channel head coil using the HR-MICRA method. Hippocampal subfields were calculated using the Automated Segmentation of Hippocampal Subfields (ASHS) package. We used the Magdeburg Young Adult 7T Atlas for sub-hippocampal structures and Penn Temporal Lobe Epilepsy T1-MRI Whole Hippocampus ASHS Atlas for general hippocampal structure and segmentation. Pearson's product-moment analyses provided correlations between biomarkers and hippocampal subfield volumes for each cerebral hemisphere. A statistical significance level of p < 0.05 was used for all analyses.
Results:
Correlations emerged between left hemisphere Cornu Ammonis (CA) 2 and G-CSF (r = -.384; p = .025); IL-10 (r = -.342; p = .048); VEGF (r = -.371; p= .031); and CA3 with IL-10 (r = -.488, p = .003); G-CSF (r = -.386; p= .024); VEGF (r = -.352; p= .041). Dentate gyrus correlated with MMP-9 (r =.416; p=.014); IL-10 (r = -.365; p =.034). BDNF was correlated with right hemisphere CA1 (r = -.417, p = .014), CA2 (r = -.497; p= .003) and CA3 (r = -.451; p=.007).
Conclusions:
In our sample of persons with MS, left hemisphere hippocampal subfield volumes were negatively correlated with inflammatory biomarkers, supporting previous reports linking inflammation to reduced brain volumes in other neurological conditions. In the right hemisphere, we found negative correlations between HIA and BDNF, suggesting a neuroprotective function for BDNF in this neurodegenerative disease. These findings in a representative sample of patients with MS highlight the need for further research exploring the relationship between HIA and systemic serum biomarkers in MS.
Ensuring test-taking validity is a crucial part of any neuropsychological evaluation. While all batteries ought to include well established test-taking validity measures regardless, it can still be helpful to be aware of an increased chance of poor performance validity prior to initiating testing. Studies repeatedly demonstrate that it is very difficult to predict which patient, particularly those without any clear incentive for poor test performance, will have invalid test performances based purely on subjective clinical judgment. Therefore, there is a need for an objective predictor of poor test taking validity. This study examines if a high endorsement of cognitive symptoms can indicate likely failure on test-taking validity measures.
Participants and Methods:
All patients at an outpatient neurological clinic completed an intake background form prior to testing. On this form, patients were asked to endorse in which, if any, of nine cognitive areas they may be experiencing difficulty (memory, attention/concentration, word finding, etc.). Patients who endorsed at least eight out of the nine clinical symptoms on the intake form were included in the current study (N=7; age range 36-43 years). All patients were clinically referred for a comprehensive neuropsychological evaluation with a variety of conditions (e.g., stroke, memory concerns, and post-COVID-19 syndrome). Importantly, none of these patients were referred within a forensic context, and therefore, they did not have any clear external motivation or secondary gain. In addition to a battery of individual neuropsychological measures, each patient was administered performance validity tests (Test of Memory Malingering, Reliable Digits, and CVLT-3 Forced Choice).
Results:
In this sample, 57% of patients who endorsed all - or nearly all - cognitive symptoms on an intake form failed test-taking validity measures. Patients who failed validity measures did not meet passing criteria on two or more embedded or independent performance validity tests. This signifies a much higher rate than the typically observed base rates (∼15%) of test-taking invalidity across non-forensic clinical settings.
Conclusions:
Preliminary findings suggest that those who indicate having cognitive problems in all (or nearly all) listed domains fail validity measures at a higher than expected rate, supporting the use of responses on a background from to indicate likely poor performance validity. Identification of high rates of symptomatic complaints, particularly symptoms that may extend beyond the initial referral question, should prompt practitioners to keenly evaluate performance validity and consider the results within the context of the patient’s presentation.
Research has established the importance of early identification and intervention for children with developmental disorders and delays. In striving toward earlier recognition and treatment of developmental concerns, it is crucial to have a universal system to monitor infant and toddler development over time. This system should comprehensively assess the desired areas of development, be based on normative data from large samples, and have strong psychometric properties. While a few developmental monitoring tools are currently in use, they lack many of the aforementioned qualities. The current study reports on the cross-sectional psychometric properties of PediaTrac, which is a novel caregiver-report measure of infant and toddler development. Specifically, this study focuses on psychometric properties of PediaTrac’s social/communication/cognition (SCG) domain during the first 9 months of life.
Participants and Methods:
The current sample included 571 caregiver-infant dyads recruited into term (n=331) and preterm (n=240) groups. Participants were from the PediaTrac multisite, longitudinal study and were socioeconomically (41.9% below median income) and racially (33.6% Black, 47.6% White, 11.0% multiracial/other) diverse. Data included caregiver reports of infant development from the SCG domain of PediaTrac at 5 sampling periods (newborn, 2, 4, 6, and 9 months). Item response theory (IRT) graded response modeling was used to estimate theta, an index of the latent trait, social/communication/cognition. Exploratory factor analysis (EFA) was used to further examine the underlying structure of the SCG domain.
Results:
Mean theta values could be reliably estimated at all time periods and followed a linear trend consistent with development. At 9 months, theta values were statistically different between the term and preterm groups, indicating that term infants demonstrated more advanced SCG abilities. Item parameters (discrimination and difficulty) could be modeled at each time period across the range of ability. Reliability of the SCG domain ranged from 0.97 to 0.99. Results of the EFA suggested a two-factor solution (affect/emotional expression, social responsiveness) at the newborn period accounting for 43% of the variance, a three-factor solution (affect/emotional expression, social responsiveness, imitation/emerging communication) at the 2-, 4-, and 6-month periods accounting for 43%, 34%, and 34% of the variance, respectively, and a four-factor solution (affect expression, social responsiveness, imitation/communication, nonverbal/gestural communication) at the 9-month period accounting for 34% of the variance.
Conclusions:
The PediaTrac SCG domain has strong psychometric properties, including reliability estimates higher than other existing caregiver-report measures of SCG abilities. EFA analyses demonstrated that the structure of affect/emotional expression and social responsiveness remains relatively stable and may reflect affective and regulatory aspects of temperament. Conversely, the quality and type of communication continually develops and becomes more differentiated throughout the time periods of interest. Notably, parents appear to be capable of observing and reliably reporting on their infants’ abilities in these areas. The use of a universal screening tool developed with rigorous psychometric methods, such as PediaTrac, could transform the way that clinicians identify infants in need of early intervention.
Empirical support for inclusion of performance validity testing (PVTs) in neuropsychological assessment continues to grow (Sweet et al., 2021). However, considerable validation is still needed to understand the impact of culturally mediated factors on the reliability of current, commonly used PVTs to accurately classify effort among various cultural groups. This study sought to contribute to the literature by examining the utility of several PVTs in a non-clinical, community-dwelling sample in Kampala, Uganda.
Participants and Methods:
Participants included 52 residents (25 Female, 27 Male) who were born between 1953-2003 from the Wabigalo community of central Kampala. Individuals were recruited by community leaders and volunteered to participate. All 52 participants were administered the Dot Counting Test (DCT; Boone et al., 2002), Test of Memory Malingering (TOMM; Tombaugh, 1997), and Rey 15-Item Memorization Test (Rey 15; Lezak, 1995). Twenty-five participants also completed Green’s Non-Verbal Medical Symptom Validity Test (NV-MSVT; Green, 2006). Data from three participants was excluded due to suspected memory concerns. Instructions for all tests were translated into Luganda by a professional translator with experience in Luganda and were administered by Luganda-speaking individuals.
Results:
Using test manual-derived cut scores, 71.4% (n = 35) participants scored in the invalid range on the DCT, 10.2% (n = 5) produced total combined scores in the invalid range on Rey 15, 6.1% (n = 3) failed TOMM Trial 2, and one participant (4.3%) exceeded cut-offs on Green’s NV-MSVT.
Conclusions:
In this non-clinical sample, manual cutoffs for DCT contributed to a high type-1 error rate. These findings suggest that culturally mediated factors may contribute to differences in engagement or performance on DCT. Future studies should explore these factors and continue to examine the utility of widely used tests in diverse samples.
Early life exposures to lead, mercury, polychlorinated biphenyls (PCBs), polybromide diphenyl ethers (PBDEs), organophosphate pesticides (OPPs), and phthalates have been associated with diminished IQ scores in children. Some studies suggest that these neurotoxicants impact boys and girls differently. We conducted a systematic review and meta-analysis to identify and quantify sex differences in IQ deficits from pre- and post-natal exposures to these developmental neurotoxicants.
Participants and Methods:
We used PubMed and PsychINFO to screen abstracts of articles published between January 1, 1950 and December 31, 2021 for empirical studies of six neurotoxicants [lead, mercury, PCBs, PBDEs, OPPs, and/or phthalates] that (1) used an individualized biomarker; (2) measured exposure during the prenatal period or within the first six years of life; and (3) provided different effect estimates on children's intellectual abilities by sex. We assessed each study for risk of bias using Navigation Guide (Woodruff & Sutton, 2014). For studies with combinable data, we performed separate random effects meta-analyses for boys and girls with subgroup analyses by neurotoxicant. To homogenize the magnitude of effect observed in each study, we recalculated results to be expressed as the absolute change in intellectual abilities for a relative change of 1.5 times (i.e., 50% increase) in the exposure variable.
Results:
Of 3205 studies screened, 53 met inclusion criteria: 34 evaluated prenatal exposure, 11 postnatal exposure, and 8 both pre- and post-natal exposure. We generally rated these studies as "low" to "probably low" risk of bias. Among the studies examining prenatal exposure, 27 reported no significant differences between the sexes, 7 found negative associations in boys, 4 found negative associations in girls, 5 found negative nonsignificant associations in boys and positive nonsignificant associations in girls, and 3 found no clear pattern, where differences by sex depended on the specific phthalate compound or outcome measurement. Among the studies examining postnatal exposure, 14 reported no significant differences between the sexes, 1 found a negative association in boys, 2 found negative associations in girls, and 2 found positive associations for either boys or girls. In our meta-analysis of 16 studies (4 lead, 4 mercury, 2 PBDEs, 2 OPPs, 4 phthalates), we found that prenatal exposure to developmental neurotoxicants was associated with decreased full-scale intelligence in boys (B = -0.26; 95% CI: -0.45, -0.08), but not girls (B = 0.09; 95% CI: -0.14, 0.31). In subgroup analyses by neurotoxicant, prenatal exposure to lead (B = -1.07; 95% CI: -1.63, -0.52), and ZPBDEs (B = -0.57; 95% CI: -1.14, -0.01) were associated with decreased full-scale intelligence in boys, whereas the girls' effect sizes were consistently near zero.
Conclusions:
During fetal development, boys appear to be more vulnerable than girls to IQ deficits from neurotoxic exposures, and especially from lead and PBDEs. More research is needed to examine the nuanced sex-specific effects found for postnatal exposures to toxic chemicals.