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Biomedical subjects

Robert A Stern

Publications and source records attributed to Robert A Stern.

16 recordsLinked to original sources

Dose-dependent white matter changes associated with repetitive head impacts in former American football players.

Repetitive head impacts sustained during American football have been associated with neuropathological changes such as white matter shear injuries. However, the impact of specific factors, such as age of first exposure and cumulative head impact burden, on white matter integrity remains unclear. This study investigated in vivo white matter microstructural changes using diffusion tensor imaging and tract-based spatial statistics in 165 male former American football players (mean age 57.3 years, range 45-74) and 52 unexposed asymptomatic male controls (mean age 59.4 years, range 45-74) in the DIAGNOSE CTE Research Project. Compared to controls, former football players exhibited significantly higher fractional anisotropy (FA) in 1.97% of the white matter skeleton (1552 voxels; Cohen's d = 0.587) and higher tissue-corrected FA (FAt) in 1.48% of the white matter skeleton (1004 voxels; Cohen's d = 0.616). No significant differences were observed for mean diffusivity, axial diffusivity, radial diffusivity, or free water between football players and controls. Among football players, there were no significant differences in the white matter microstructure between players diagnosed with traumatic encephalopathy syndrome and those without the diagnosis. Lower FA was significantly associated with older age (P < 0.00001) and an earlier age of first exposure to tackle football (P < 0.01), while lower FAt was associated with greater cumulative head impact burden, specifically higher linear acceleration (P < 0.04) and rotational force (P < 0.02). This study highlights the influential role of exposure factors on white matter microstructure in former American football players, as well as the utility of diffusion tensor imaging to aid in characterizing the long-term effects of repetitive head impacts in contact sport athletes.

American football↗

Regional ventricular enlargement as an in vivo biomarker of cumulative biomechanical neurodegeneration in former American football players.

INTRODUCTION: Repetitive head impacts (RHIs) have been linked to later life neurodegeneration, yet the in vivo structural correlates of cumulative biomechanical loading remain unclear. We examined whether regional ventricular morphology in former American football players reflects exposure burden and traumatic encephalopathy syndrome (TES) classification. METHODS: Participants included 170 male former football players and 54 age-matched asymptomatic male controls from the Diagnostics, Imaging, and Genetics Network for the Objective Study and Evaluation of Chronic Traumatic Encephalopathy Research Project. Subject-specific manual segmentation quantified lateral ventricle, inferior horn, third ventricle, and fourth ventricle volumes. Group and exposure associations were tested using generalized least squares models. RESULTS: Former players showed larger left inferior lateral ventricle volume than controls, with the largest effects among professional players. Greater cumulative linear and rotational acceleration exposure was associated with enlargement across lateral ventricular and inferior horn regions. DISCUSSION: Regional ventricular enlargement may represent an in vivo marker of cumulative biomechanical loading after RHI exposure.

Humans↗

The influence of cognitive reserve on neuropsychological functioning following coronary artery bypass grafting (CABG).

Neuropsychological impairment is common, yet variable, after coronary artery bypass grafting (CABG). Similar variability has been observed in other CNS-related diseases. Empirical findings in Alzheimer's disease and HIV, among other areas, suggest cognitive reserve (CR) may mediate the cognitive impact of these diseases. The present study examined whether CR mediates neuropsychological outcome after CABG. Participants were 42 (N=42) individuals who underwent elective, normothermic CABG. Each was placed in high (n=22) or low (n=20) CR groups based on estimated premorbid intelligence and occupational attainment. All were administered neuropsychological tests preoperatively and at discharge. The total incidence of neuropsychological decline (66.7%) was not significantly different between CR groups. However, on working memory and executive function tests, specifically, the high CR group demonstrated greater post-operative decline compared to the low CR group. These data are considered in the context of a threshold model of CR theory.

Aged↗

Cognitive correlates of HVOT performance differ between individuals with mild cognitive impairment and normal controls.

OBJECTIVE: To clinically characterize performance on the Hooper Visual Organization Test (HVOT) among participants with mild cognitive impairment (MCI) and to identify naming and executive functioning correlates associated with HVOT performance among MCI participants and normal controls (NC). BACKGROUND: The HVOT is a common neuropsychological instrument that measures visuospatial skills and agnosia. It has, however, been criticized for its multifactorial nature, as several studies have reported executive or language correlates of HVOT performance. To our knowledge, simultaneous comparison of executive functioning and language demands of the HVOT has never been performed among an older cohort. METHODS: The HVOT, two tests of executive functioning [Trail Making Test, Part B (TMT-B), Controlled Oral Word Association (COWA)] and two tests of naming [abbreviated Boston Naming Test (BNT), Animal Naming] were administered to 222 NC, 166 MCI, and 68 Alzheimer's disease (AD) individuals. RESULTS: HVOT scores were significantly different between all three groups in the expected direction (AD<MCI<NC). Linear regression among NC participants revealed that COWA, age, and BNT were significantly associated with HVOT scores, accounting for 12%, 6%, and 4% of HVOT variance, respectively. Among MCI participants, the BNT accounted for 43% of HVOT variance. Neither TMT-B nor Animal Naming was a significant predictor for either group. CONCLUSION: Among NC participants, rapid word generation (i.e., COWA), a measure of executive functioning, is the most salient predictor of HVOT performance. In contrast, lexical retrieval (i.e., BNT) is the most salient language or executive functioning predictor of HVOT performance among MCI participants. These findings extend previous claims that the HVOT is multifactorial by suggesting that reduced HVOT performance in MCI patients may be related to mild lexical retrieval impairments.

Aged↗

Driving scenes test of the Neuropsychological Assessment Battery (NAB) and on-road driving performance in aging and very mild dementia.

The Driving Scenes test of the new Neuropsychological Assessment Battery (NAB; [Stern, R.A., & White, T. (2003a). Neuropsychological Assessment Battery. Lutz, FL: Psychological Assessment Resources, Inc.]) measures several aspects of visual attention thought to be important for driving ability. The current study examined the relationship between scores on the Driving Scenes test and on-road driving performance on a standardized driving test. Healthy participants performed significantly better on the Driving Scenes test than did very mildly demented participants. A correlation of 0.55 was found between the brief, office-based Driving Scenes test and the 108-point on-road driving score. Furthermore, the Driving Scenes test scores differed significantly across the driving instructor's three global ratings (safe, marginal, and unsafe), and results of a discriminant function analysis indicated that the Driving Scenes test correctly classified 66% of participants into these groups. Thus, the new NAB Driving Scenes test appears to have good ecological validity for real-world driving ability in normal and very mildly demented older adults.

Aged↗

Accuracy of ED triage of psychiatric patients.

The study objective was to determine the accuracy of initial triage assessment (ITA) in directing behavioral emergency patients to appropriate medical or psychiatric care, and to identify variables that enhance triage accuracy. A cohort study of 436 adult patients with 1 of 10 behavioral-related complaints was conducted. ITA compared with the final ED diagnosis, both of which were classified as either "medical" or "psychiatric." Patient triage characteristics correlated with the final ED diagnosis using logistic regression. Sensitivity of ITA for predicting a medical final ED diagnosis was 70% (95% CI 60.1, 78.5) and specificity 85% (95% CI 80.6, 88.7). ITA agreed with final ED diagnosis in 344 (81.3%) and these patients had a significantly shorter ED length of stay (4.50 v 5.90 hours, p=0.03). Dementia, past psychiatric history, family history of psychiatric illness, and ITA were significant predictors of final ED diagnosis. ITA is a fair predictor of the final ED diagnosis, but could be enhanced by screening for dementia and past psychiatric history. Improved triage accuracy could reduce length of stay for such patients.

Adult↗

Preliminary study of the relationship between thyroid status and cognitive and neuropsychiatric functioning in euthyroid patients with Alzheimer dementia.

OBJECTIVE: To investigate whether variations within normal ranges of thyroid functioning are related to cognitive and neuropsychiatric functioning in Alzheimer disease (AD). BACKGROUND: Mild alterations of thyroid hormone levels, even in the normal range, are associated with changes in mood and cognitive functioning in older, nondemented adults, and lower concentrations of thyroid hormones have been shown to be associated with an increased risk for cognitive decline. Less is known about the relationship between thyroid hormone levels and cognitive and neuropsychiatric dysfunction in AD. METHOD: Twenty-eight euthyroid patients with AD on donepezil underwent evaluation of thyroid status, including measures of thyroid-stimulating hormone (TSH) and free thyroxine (FT4), and cognitive and neuropsychiatric assessment with the Alzheimer's Disease Assessment Scale, Neuropsychiatric Inventory, and Visual Analog Mood Scales. RESULTS: Correlational analyses indicated statistically significant associations between FT4 concentrations and self-reported feelings of fear and fatigue. Fear and fatigue were negatively correlated with FT4. There were no significant relationships between thyroid hormones and cognition and other depressive and anxiety symptoms. CONCLUSIONS: Results of this preliminary study support a relationship between thyroid status and neuropsychiatric symptoms in euthyroid individuals with AD, with lower concentrations of FT4 associated with fear and fatigue.

Affective Symptoms↗

Cognitive and neuropsychiatric aspects of subclinical hypothyroidism: significance in the elderly.

The effects of overt hypothyroidism (HO) on cognition and mood are well established, and HO is considered a common cause of reversible dementia. There is now increasing evidence to suggest that subclinical hypothyroidism (ie, elevated thyroid stimulating hormone in the presence of normal thyroxine concentrations) may be a predisposing factor for depression, cognitive impairment, and dementia. Subclinical hypothyroidism is more common than HO and is most prevalent in the elderly, particularly in women. Older adults may be more vulnerable to the effects of subclinical hypothyroidism, given age-related changes to the hypothalamic-pituitary-thyroid axis, and there is an association between thyroid status and cognitive decline and dementia in the elderly. The purpose of this review is to summarize existing data on the cognitive and neuropsychiatric consequences of subclinical hypothyroidism, benefits of treatment, and recommendations for screening and monitoring in older adults.

Aged↗

Utility of the neuropsychological evaluation in an acute medical hospital.

Although recent studies have demonstrated the importance of cognitive assessment in medical settings in general, there have been no specific studies addressing the utility of the neuropsychological evaluation in the acute inpatient hospital setting. The current study examined the use of inpatient neuropsychological evaluation by treating physicians in an acute medical hospital for patient care and discharge disposition. Participants were 100 inpatients within an urban medical center who received a neuropsychological evaluation. Results showed 78% of hospital discharge summaries included information regarding the neuropsychological evaluation, 48% referenced specific results, and 68% reported specific recommendations. Further, actual placement outcomes were consistent with the neuropsychological evaluation placement recommendations 80% of the time. The current study supports the utility of neuropsychological evaluations on overall inpatient care, and discusses ways in which the results may be used to communicate the value of neuropsychological services to medical treatment and discharge planning teams, third party payors, and medical center administrators.

Female↗

Discrimination of dementia with lewy bodies from Alzheimer disease and Parkinson disease using the clock drawing test.

OBJECTIVE: The authors' objective was to examine the ability of the Clock Drawing Test to discriminate Dementia with Lewy bodies from Alzheimer disease and Parkinson disease. BACKGROUND: Recent advances in medical treatments for dementia underscore the importance of differentiating among dementia subtypes. Clinically, Dementia with Lewy bodies can often be difficult to discriminate from Alzheimer disease and Parkinson disease because of similar and overlapping cognitive and motor features. While the Clock Drawing Test has been shown to discriminate dementia from normal aging fairly accurately, less is known about its ability to discriminate between various dementia groups. METHODS: Patients with Alzheimer disease (n = 22), patients with cognitively impaired Parkinson disease (n = 17), and patients with Dementia with Lewy bodies (n = 20), matched for age, education, and dementia severity, were compared on the Clock Drawing Test, scored for overall accuracy as well as the presence of specific error types. RESULTS: There were no significant group differences on a global quantitative measure of Clock Drawing Test performance. With regard to differences on the error types evaluated, the patients with Dementia with Lewy bodies were more likely to make conceptual errors than the patients with Alzheimer disease and Parkinson disease, and the patients with Parkinson disease and Dementia with Lewy bodies made more planning errors than the patients with Alzheimer disease. Classification accuracy was fair, with 69% overall classification for Alzheimer disease versus Dementia with Lewy bodies, and 68% overall classification for Parkinson disease versus Dementia with Lewy bodies. CONCLUSIONS: Although some differences may exist in the qualitative features of clock drawing performance between these patient groups, overall clock drawing performance is relatively similar, and as a single instrument, the Clock Drawing Test provides limited discrimination of Dementia with Lewy bodies from Alzheimer disease and Parkinson disease.

Aged↗

Odor identification deficits in diffuse lewy body disease.

OBJECTIVES: To describe odor identification performance in patients with diffuse Lewy body disease and determine the clinical utility of odor identification tests in distinguishing diffuse Lewy body disease from Alzheimer disease. BACKGROUND: The presence of olfactory deficits, especially odor identification deficits, has been well established in both Alzheimer disease and Parkinson disease. The presence of olfactory deficits in diffuse Lewy body disease is also likely given the overlap of clinical symptoms and neuropathology with Alzheimer disease and Parkinson disease. However, odor identification abilities have not been described previously in diffuse Lewy body disease. METHODS: Nine patients from a clinic sample with diffuse Lewy body disease and nine carefully matched patients with Alzheimer disease were administered an odor identification task as part of their neuropsychologic evaluations. RESULTS: Patients with diffuse Lewy body disease performed significantly worse than patients with Alzheimer disease on the odor identification test. CONCLUSIONS: Odor identification deficits may be more prevalent and severe in people with diffuse Lewy body disease than in people with Alzheimer disease, and olfactory testing may be useful in antemortem differential diagnosis of the two disorders.

Aged↗

The influence of cognitive reserve on memory following electroconvulsive therapy.

Cognitive reserve (CR) theory proposes that certain genetic and nonacquired variables, such as larger head size and greater neuronal density, and some life experiences, such as higher educational and occupational attainment, provide a buffer against brain dysfunction in the face of acquired central nervous system (CNS) dysfunction. This study examined CR in the pseudoexperimental paradigm of electroconvulsive therapy (ECT). Subjects included fifty (N = 50) depressed patients treated with bilateral ECT. Subjects were placed in high (n = 27) or low (n = 23) CR groups based on years of education and occupational attainment. At baseline, no significant differences were observed between the groups in the amount of information forgotten on a verbal memory measure (Randt stories) after a 30-minute delay. Following three ECT treatments, however, the high CR group forgot significantly less information after a 30-minute delay, as compared to the low CR group (p < 0.01). These data provide further support for CR theory and suggest that CR may be an underlying factor in differential memory loss in ECT.

Adult↗

Neurocognitive Manifestations of Human Immunodeficiency Virus.

Is human immunodeficiency virus still a terminal condition? Recent advances in treatment have significantly reduced both mortality and morbidity associated with HIV, but these treatments have not been successful in eradicating the virus itself. As such, HIV has evolved into a chronic condition that is complicated by neurocognitive factors. Cognitive difficulties associated with HIV are characterized by a subcortical pattern with primary deficits in information processing speed and psychomotor speed. These deficits interfere with the ability of patients to complete important instrumental activities of daily living even in the absence of dementia. Treatment of HIV improves neurocognitive functioning, but the regimens are complex and patient adherence is critical. Cognitive factors can negatively impact treatment adherence, which in turn results in poorer immunological, cognitive, and psychiatric outcome. This cycle emphasizes the important interrelationships between symptom expression and treatment outcome in patients with HIV. The nature of these relationships will change with further developments in treatment regimens such as once-daily dosing. Less complex treatment approaches should improve health outcome as well as provide additional opportunities to further understand the impact of HIV on brain function.

Journal Article↗

Referring physicians' perceptions of the neuropsychological evaluation: how are we doing?

Clinical neuropsychologists often serve as consultants to physicians. However, little is known about physicians' perceptions of the neuropsychological evaluation. Therefore, the present study examined the opinions of physicians who referred patients for neuropsychological evaluation. Surveys were mailed with the neuropsychological reports to 119 physicians who referred patients to an outpatient hospital-based neuropsychology practice over a 2-year period. Results showed that physicians requesting neuropsychological evaluations most commonly sought assistance with establishing and confirming a diagnosis, and they reported a high level of satisfaction with the evaluation, including strong agreement with diagnosis and recommendations. These findings did not differ based on physician specialty or patient diagnosis.

Attitude of Health Personnel↗

Assessment of mood state in dementia by use of the visual analog mood scales (VAMS).

OBJECTIVE: The assessment of mood states in individuals with dementia is a challenging yet clinically useful task. The purpose of the present study was to examine the validity of the Visual Analog Mood Scales (VAMS) in individuals with dementia. METHODS: Thirty-one patients who met diagnostic criteria for dementia completed the VAMS and a modified Profile of Mood States. RESULTS: Authors found good convergent validity between all monotrait-heteromethod mood states. Excellent discriminant validity was found for VAMS Happy, Confused, Angry, and Energetic scales. CONCLUSION: These results provide evidence for the validity of the VAMS in patients with dementia.

Aged↗