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25 Longitudinal Decline in Memory in 1991 Gulf War Veterans: Where you Start Matters.
- Leah A Orlinsky, Kathryn A Price, Clara G Zundel, Kimberly Sullivan, Maxine H Krengel
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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. 815-816
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Objective:
Memory complaints have been a concern of Gulf War (GW) veterans since their return from the war in 1991, and over time it has been reported that exposures to neurotoxicants during the war have been associated with memory decline from premorbid levels. However, many of the studies that have shown slight or no memory decrements only looked at one time point and have not followed participants to document trajectory of symptoms over time. Longitudinal design is an optimal way to document change in cognitive function over time and the Fort Devens cohort (FDC), the longest running cohort of GW veterans, is ideal for assessing such change. This prospectively designed non-treatment seeking cohort were assessed at multiple timepoints with neuropsychological assessments and surveys. Initial neuropsychological assessments from 1997 showed above average scores on tests of verbal memory (California Verbal Learning Test) and average nonverbal memory (Wechsler Memory Scale-R) performances. A follow-up study of neuropsychological testing was completed between 2019-2022. This study was designed to document change in cognitive status between the two time points.
Participants and Methods:Participants (N=50) from the original 1991 cohort were again tested from 2019-2022. Neuropsychological tests included California Verbal Learning Test-Second edition (CVLT2) for verbal learning, and the visual reproduction subtest from the Wechsler Memory Scale-Revised (WMS-R) for nonverbal learning and memory. For both time points, the average scores of the participants were compared with age scaled scores for each neuropsychological test.
Results:The mean age of our current participants was 58 years. 72% were men. Relative to standardized test norms at the first time point, the scores for total learning from trials 1 through 5 from the CVLT2 were in the above average range relative to age and gender-based norms. During the second time point, the participants average scores on the same scale had dropped to the average range, one full standard deviation below their prior performances. In addition, at the first time point, total learning from visual reproductions was in the average range and dropped to the low average range for the second time point. This value dropped by one-half a standard deviation.
Conclusions:Results showed significant diminishment in verbal and visual memory relative to prior test performances. Whenever possible, documenting the trajectory of symptoms relative to where each participant started on neuropsychological functional outcomes is key to understanding the longitudinal impact of neurotoxicant and other war-related exposures in military veterans. Given this decline, further assessment of GW veterans’ cognitive trajectories is warranted.
24 Longitudinal Neuropsychological Functioning in Gulf War Veterans Exposed to Neurotoxicants and War-Related Trauma
- Kathryn A Price, Leah A Orlinsky, Clara G Zundel, Kimberly Sullivan, Maxine H Krengel
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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. 814-815
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Objective:
Gulf War (GW) veterans were exposed to many neurotoxicants during the 1990-1991 Gulf War. Neurotoxicants included: chemical warfare such as sarin nerve gas, combustion byproducts from oil well fires and diesel fuels from tent heaters, pesticides, and prophylactic anti- nerve gas pyridostigmine bromide pills (PB); all of which have been associated with both cognitive and mood concerns. There are few longitudinal studies that have examined cognitive functioning regarding these toxicant exposures. In our longitudinal Fort Devens cohort, we found decrements over time in the area of verbal learning and memory but no differences in measures of nonverbal memory and executive function. To describe changes more accurately over time in this GW veteran cohort, we examined cognitive functioning in those with probable Post-Traumatic Stress Disorder (PTSD) versus those without.
Participants and Methods:The FDC is the longest running cohort of GW veterans with initial baseline cognitive, mood, exposure and trauma assessments in 1997-1998 and follow-up evaluations in 2019-2022. FDC veterans (N=48) who completed both time points were the participants for this study. Veterans were categorized into dichotomous (yes/no) groups of PTSD classification. The PTSD checklist (PCL) was used to determine PTSD case status. Symptom ratings on the PCL were summed (range:17-85) and a cutoff score of 36 or higher was utilized to indicate probable PTSD. Neuropsychological measures of mood (POMS) and memory (Visual Reproductions from the Weschler Memory Scale-R; California Verbal Learning Test Second Edition; CVLT2) and executive function and language; (Delis-Kaplan Executive Function System- Color Word and Verbal fluency- Animals) were compared overtime using Paired T-tests.
Results:The study sample (N=48) was 92% male and 96% reported active-duty status at the time of the GW. Mean current age was 58 years. All veterans reported exposure to at least one war-related toxicant. 48% met criteria for probable PTSD (N = 23) while 52% did not (n=25). No differences between groups were found in any of the POMS subscales, nor were differences seen in verbal memory, executive function, or language tasks. There were, however, significant differences in nonverbal memory in those with probable PTSD showing fewer details recalled during delay on the WMS-R Visual Reproductions (p<0.05).
Conclusions:In this longitudinal analysis, GW veterans with PTSD showed declines in nonverbal memory and consistent levels of function in all other tasks. Basic mood scales did not show decline; therefore, these results are not due to generalized changes in mood. All participants reported at least one neurotoxicant exposure and we did not have the power to examine the impact of the individual exposures, thus we cannot rule any contributing factors other than PTSD. This study highlights the importance of longitudinal follow up and continual documentation of GW veterans’ memory performance and their endorsement of mood symptoms overtime. Specifically, these findings reveal that future studies should examine the prolonged course of memory and mood symptomatology in GW veterans who have endorsed a traumatic experience.
Dynamic Mechanical Analysis and Dielectric Relaxation for Second Order Nonlinear Optical Applications
- Leah A. Sullivan, Hilary S. Lackritz
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- Journal:
- MRS Online Proceedings Library Archive / Volume 392 / 1995
- Published online by Cambridge University Press:
- 21 February 2011, 69
- Print publication:
- 1995
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Relaxation dynamics of poly(methyl methacrylate) (PMMA) and doped PMMA systems are investigated as a function of processing temperature and frequency. Polymer relaxations and changes in local mobility are responsible for chromophore reorientation and lead to a loss in second-order nonlinear optical (NLO) properties. Studying polymer relaxations enables the temporal and thermal stability of the NLO polymer systems to be more accurately and readily predicted. The polymer dynamics are studied by correlating mechanical and dielectric relaxations to polymer and chromophore relaxations that occur during chromophore reorientation in second harmonic generation experiments. Dielectric and mechanical relaxation techniques enable polymer relaxation dynamics to be observed over a broad frequency range. The plasticization effect of the NLO chromophores on the polymer relaxation dynamics is also investigated.