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35 The Effect of Diagnostic Method on Racial Disparities in Mild Cognitive Impairment and Dementia Diagnosis Using the NACC Database.
- Jennifer L Nosker, Stephen L Aita, Nicholas C Borgogna, Tina Jimenez, Keenan A Walker, Tasha Rhoads, Janelle M Eloi, Zachary J Resch, Victor A Del Bene
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 909-910
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Objective:
Population studies have shown that Black individuals are at higher risk for MCI and dementia than White individuals but are more likely to be underdiagnosed or misdiagnosed. Although multiple contributory factors have been identified in relation to neurocognitive diagnostic disparities among persons of color, few studies have investigated race-associated differences in MCI and dementia classification across diagnostic methods. The current study examined the agreement of cognitive classification made via semi-structured interview and neuropsychological assessment.
Participants and Methods:Only participants assigned normal cognitive status or cognitive impairment with presumed Alzheimer’s etiology were included in the study. Baseline visit data in the National Alzheimer’s Coordinating Center (NACC) dataset was collected to compare correspondence of cognitive classification (normal cognition, MCI, dementia) via semi-structured interview (Clinical Dementia Rating; CDR) with formal NACC diagnostic determination. NACC diagnostic determination was further separated by single clinician and consensus diagnostic methods. Inter-rater agreement was evaluated using chi-squared tests, and respective analyses were stratified for race (Black vs White), ethnicity (Hispanic vs Non-Hispanic), and education (<12 years vs. >12 years).
Results:The sample size included 4,739 Black and 26,393 White participants across 43 Alzheimer’s Disease Research Centers (ADRCs). Inter-rater analyses between CDR (semi-structured interview) versus single-clinician and formal consensus NACC diagnostic methods showed strong (all (pc>.70) consistency in cognitive diagnoses overall, irrespective of race, ethnicity, and education. The percentage of agreement between diagnostic methods was nearly 100% for those categorized as cognitively normal or with dementia. However, the agreement for MCI was considerably lower (ranging from 28-74%) and revealed a disparity in diagnostic method between Black and White individuals. White individuals diagnosed with MCI via CDR (CDR total =0.5) were more likely to be labeled as having dementia regardless of NACC diagnostic method. However, Black individuals diagnosed with MCI via CDR were equally likely to be diagnosed as cognitively normal or with dementia via the formal consensus method.
Conclusions:Irrespective of race and other demographic variables, diagnostic methods had high agreement for groups labeled with normal cognition and dementia. Agreement was consistently lower for the group labeled with MCI, with Black individuals having greater variability in diagnostic differentials when diagnosed via formal consensus method. The results of the study suggest that neuropsychological assessment continues to be an integral component of diagnosing individuals with MCI, reducing possible sources of bias.
6 Improved verbal fluency following unilateral right hemisphere subthalamic nucleus deep brain stimulation for Parkinson’s disease: Is implant hemisphere a modifiable risk factor for cognitive decline?
- Victor A Del Bene, Roy C Martin, Sarah A Brinkerhoff, Joseph W Olson, Dario Marotta, Christopher L Gonzalez, Kelly A Mills, J Nicole Bentley, Barton L Guthrie, Harrison C Walker
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 112-113
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Objective:
Non-motor symptoms, such as mild cognitive impairment and dementia, are an overwhelming cause of disability in Parkinson’s disease (PD). While subthalamic nucleus deep brain stimulation (STN DBS) is safe and effective for motor symptoms, declines in verbal fluency after bilateral DBS surgery have been widely replicated. However, little is known about cognitive outcomes following unilateral surgeries.
Participants and Methods:We enrolled 31 PD patients who underwent unilateral STN-DBS in a randomized, cross-over, double-blind study (SUNDIAL Trial). Targets were chosen based on treatment of the most symptomatic side (n = 17 left hemisphere and 14 right hemisphere). All participants completed a neuropsychological battery (FAS/CFL, AVLT, DKEFS Color-Word Test) at baseline, then 2, 4, and 6 months post-surgery. Outcomes include raw scores for verbal fluency, immediate and delayed recall, and DKEFS Color-Word Inhibition trial (Trial 3) completion time. At 2, 4, and 6 months, the neurostimulation type (directional versus ring mode) was randomized for each participant. We compared baseline scores for all cognitive outcome measures using Welch’s two-sample t-tests and used linear mixed effects models to examine longitudinal effects of hemisphere and stimulation on cognition. This test battery was converted to a teleneuropsychology administration because of COVID-19 mid-study, and this was included as a covariate in all statistical models, along with years of education, baseline cognitive scores, and levodopa equivalent medication dose at each time point.
Results:At baseline, patients who underwent left hemisphere implants scored lower on verbal fluency than right implants (t(20.66) = -2.49, p = 0.02). There were not significant differences between hemispheres in immediate recall (p = 0.57), delayed recall (p = 0.22), or response inhibition (p = 0.51). Post-operatively, left STN DBS patients experienced significant declines in verbal fluency over the study period (p = 0.02), while patients with right-sided stimulation demonstrated improvements (p < .001). There was no main effect of stimulation parameters (directional versus ring) on verbal fluency, memory, or inhibition, but there was a three-way interaction between time, stimulation parameters, and hemisphere on inhibition, such that left STN DBS patients receiving ring stimulation completed the inhibition trial faster (p = 0.035). After surgery, right STN DBS patients displayed faster inhibition times than patients with left implants (p = 0.015).
Conclusions:Declines in verbal fluency after bilateral stimulation are the most commonly reported cognitive sequalae of DBS for movement disorders. Here we found group level declines in verbal fluency after unilateral left STN implants, but not right STN DBS up to 6 months after surgery. Patients with right hemisphere implants displayed improvements in verbal fluency. Compared to bilateral DBS, unilateral DBS surgery, particularly in the right hemisphere, is likely a modifiable risk factor for verbal fluency declines in patients with Parkinson’s disease.
49 Subjective and Objective Psychophysical Olfactory Dysfunction in Men Living with HIV
- Christopher Collette, Vidyulata Kamath, Victor A Del Bene, Alexandra Jacob, Pariya Fazeli, David E Vance
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 46-47
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Objective:
Olfactory dysfunction can influence nutritional intake, the detection of environmental hazards, and quality of life. Prior research has found discordance between subjective and objective measures of olfaction. In people living with HIV (PLWH), olfactory dysfunction is widely reported; however, few studies have examined concordance between subjective olfactory self-ratings and performance on an objective psychophysical measure of olfaction and associated factors in men living with HIV (MLWH).
Participants and Methods:MLWH (n=51, mean age=54 years, 66.7% Black) completed two subjective olfaction ratings (two 5-point Likert scales), the Smell Identification Test (SIT), cognitive measures (HVLT-R, TMT), and self-report questionnaires assessing smell habits, mood, cognitive failures, and quality of life. Participants were categorized into one of four groups: true positives (TP; impaired subjective olfaction and objective olfaction dysfunction), false negatives (FN; intact subjective olfaction and objective olfaction dysfunction), false positives (FP; impaired subjective olfaction and objective normosmia), and true negatives (TN; intact subjective olfaction and normosmia). Established formulas were used to calculate the sensitivity and specificity of subjective olfaction, and t-tests and ANOVA were used to examine potential demographic, clinical, and cognitive factors contributing to discordance between subjective and objective olfaction dysfunction.
Results:Across both subjective self-report items, 35.3% reported olfactory dysfunction, whereas 60.8% had objective olfaction dysfunction on the SIT (score < 33). Black MLWH had significantly higher rates of subjective (Black 41.2% vs. White 35.3%) and objective (Black 73.5% vs. White 35.3%) olfactory dysfunction (X2(1)=9.22, p=.002). We found discordance between subjective and objective olfaction measures, with 29.4% of the sample having objective olfaction dysfunction and not recognizing it (FN). In comparison, 3.9% with self-rated olfaction impairment had normal objective olfaction scores (FP). Additionally, there was concordance in subjective self-reports compared with objective olfaction, with 35.3% correctly identifying normal olfaction (TN) and 31.4% correctly identifying olfactory dysfunction (TP). Those unaware of olfaction dysfunction (FN) reported using less scented products in daily life on the Smell Habits Questionnaire. Although the FN group had faster TMT scores, these findings were no longer significant after the removal of three outliers in the TP group (e.g., time to complete greater than 350 seconds).
Conclusions:Our findings cohere with work in healthy older adults, traumatic brain injury, and Parkinson’s disease, documenting that subjective olfaction may inadequately capture the full range of a person’s olfactory status. We extend these findings to a sample of MLWH, in which discordance rates ranged from 35-61% for subjective and objective olfactory dysfunction. Unawareness of olfactory dysfunction in MLWH was associated with less daily smell habits and paradoxically faster TMT performance. A higher number of smell habits in the TP group indicate that more frequent odor exposure may increase sensitivity to olfactory declines. Future studies with larger samples will be helpful in understanding the full nature of these relationships. Lastly, given that one-third of the sample had discordance between subjective and objective olfaction, objective olfaction measures may be useful to consider in the neuropsychological assessment and standard clinical care for PLWH.