Changes in the performance of parkinsonian patients and normal aged on the Benton Visual Retention Test

Influence of cognitive reserve on cognitive and motor function in α-synucleinopathies: A systematic review and multilevel meta-analysis

Cognitive reserve has shown promise as a justification for neuropathologically unexplainable clinical outcomes in Alzheimer's disease. Recent evidence suggests this effect may be replicated in conditions like Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. However, the relationships between cognitive reserve and different cognitive abilities, as well as motor outcomes, are still poorly understood in these conditions. Additionally, it is unclear whether the reported effects are confounded by medication. This review analysed studies investigating the relationship between cognitive reserve and clinical outcomes in these α-synucleinopathy cohorts, identified from MEDLINE, Scopus, psycINFO, CINAHL, and Web of Science. 85 records, containing 176 cognition and 31 motor function effect sizes, were pooled using multilevel meta-analysis. There was a significant, positive association between higher cognitive reserve and both better cognition and motor function. Cognition effect sizes differed by disease subtype, cognitive reserve measure, and outcome type; however, no moderators significantly impacted motor function. Review findings highlight the clinical implications of cognitive reserve and importance of engaging in reserve-building behaviours.

Patients with Parkinson's disease demonstrate deficits in visual-spatial memory in the Chinese Visual Retention Test

OBJECTIVE

We aimed to explore the existence of visual-spatial memory deficit in patients with Parkinson's disease (PD) without dementia in the Chinese Visual Retention Test, as well as to assess whether their performance is related to age, duration, severity, stage, and dopamine (DA) dose.

METHODS

Forty-two patients with PD and 30 healthy controls were included in our study. The Chinese Visual Retention Test was used to evaluate the visual-spatial memory of the subjects. Parameters of the Chinese Visual Retention Test were compared between the two groups. Correlation analysis and multiple linear regression analysis were used to explore the associations of the Chinese Visual Retention Test with age, duration, severity, stage of PD, and DA dose.

RESULTS

Three correct scores in the Chinese Visual Retention Test were all significantly lower in the PD group than in the control group. The total error scores, error scores of omissions, deformation, and persistence in the PD group were significantly higher than those in the control group. Correlation analysis showed the total error scores in the Chinese Visual Retention Test was positively correlated with UPDRS III score and H-Y classification. Multiple linear regression analysis showed that the total error scores in the Chinese Visual Retention Test were associated with the UPDRS III score and H-Y classification.

CONCLUSION

Patients with PD without dementia had visual-spatial memory deficits in the Chinese Visual Retention Test which may be affected by the severity and clinical stage of PD.

A Novel Method for the Development of Environmental Public Health Indicators and Benchmark Dose Estimation Using a Health-Based End Point for Chlorpyrifos

BACKGROUND

Organophosphorus (OP) compounds are the most widely used group of insecticides in the world. Risk assessments for these chemicals have focused primarily on 10% inhibition of acetylcholinesterase in the brain as the critical metric of effect. Aside from cholinergic effects resulting from acute exposure, many studies suggest a linkage between cognitive deficits and long-term OP exposure.

OBJECTIVE

In this proof-of-concept study, we focused on one of the most widely used OP insecticides in the world, chlorpyrifos (CPF), and utilized an existing physiologically based pharmacokinetic (PBPK) model and a novel pharmacodynamic (PD) dose-response model to develop a point of departure benchmark dose estimate for cognitive deficits following long-term, low-dose exposure to this chemical in rodents.

METHODS

Utilizing a validated PBPK/PD model for CPF, we generated a database of predicted biomarkers of exposure and internal dose metrics in both rat and human. Using simulated peak brain CPF concentrations, we developed a dose-response model to predict CPF-induced spatial memory deficits and correlated these changes to relevant biomarkers of exposure to derive a benchmark dose specific to neurobehavioral changes. We extended these cognitive deficit predictions to humans and simulated corresponding exposures using a model parameterized for humans.

RESULTS

Results from this study indicate that the human-equivalent benchmark dose (BMD) based on a 15% cognitive deficit as an end point is lower than that using the present threshold for 10% brain AChE inhibition. This predicted human-equivalent subchronic BMD threshold compares to occupational exposure levels determined from biomarkers of exposure and corresponds to similar exposure conditions where deficits in cognition are observed.

CONCLUSIONS

Quantitative PD models based on neurobehavioral testing in animals offer an important addition to the methodologies used for establishing useful environmental public health indicators and BMDs, and predictions from such models could help inform the human health risk assessment for chlorpyrifos. https://doi.org/10.1289/EHP1743.

The robust reliability of neuropsychological measures: meta-analyses of test-retest correlations

Test-retest reliability is an important psychometric property relevant to assessment instruments typically used in neuropsychological assessment. This review presents a quantitative summary of test-retest reliability coefficients for a variety of widely used neuropsychological measures. In general, the meta-analytic test-retest reliabilities of the test scores ranged from adequate to high (i.e., r=.7 and higher). Furthermore, the reliability values were largely robust across factors such as age, clinical diagnosis, and the use of alternate forms. The values for some of the memory and executive functioning scores were lower (i.e., less than r=.7). Some of the possible reasons for these lower values include ceiling effects, practice effects, and across time variability in cognitive abilities measured by those tests. In general, neuropsychologists who use these measures in their assessments can be encouraged by the magnitude of the majority of the meta-analytic test-retest correlations obtained.

A technique for removal of the visuoperceptual component from tracking performance and its application to Parkinson's disease

Although it is well established that subjects with Parkinson's disease perform poorly on complex sensory-motor tasks, the extent to which this is due to visuoperceptual deficits is unclear. We measured the performance of 16 patients with Parkinson's disease, both on and off drugs, and 16 age and sex matched control subjects on preview and nonpreview tracking tasks and a nonmotor test of dynamic visuoperception. Order effects were controlled for by a randomized cross-over design. Performance on the perceptual task was measured in terms of perceptual resolution and was found impaired in the Parkinsonian group. The contribution of visuoperceptual function to tracking performance was removed using the concept of a visuoperceptual buffer-zone. The mean tracking error remained impaired on all tracking tasks and demonstrated that limitations is visuoperceptual function play only a minor role in the tracking errors in both Parkinsonian and control subjects. It is clear that the technique for determining the visuoperceptual component of performance on complex sensory-motor tasks has considerable scope for application in studies of a variety of brain disorders.

Fractionation of visuoperceptual dysfunction in Parkinson's disease

There is considerable evidence that visuoperceptual function is impaired in Parkinson's disease although this view remains contentious. The issue is confounded by studies which have demonstrated impairment of visual sensation, in particular high-contrast visual acuity, in Parkinson's disease. We have measured the visuoperceptual performance of 16 patients with mild to moderate Parkinson's disease, both on and off drugs, and 16 age and sex matched control subjects on non-motor tests of visual resolution, static perception, and dynamic perception. Performance on the perceptual tasks was measured in terms of perceptual resolutions and was found impaired in the parkinsonian group. After removal of the contribution of poorer visual resolution, the overall visual perception remained impaired, although to a relatively subtle degree, such that the difference between the two groups on its static and dynamic components did not reach significance.

Assessment of intellectual functioning of patients with Parkinson's disease using the Satz-Mogel (1962) short form of the Wechsler Adult Intelligence Scale

The purpose of the present study was to compare the Satz-Mogel (S-M) short form of the Wechsler Adult Intelligence Scale--Revised (WAIS-R) with the full-scale WAIS-R to establish its utility in the assessment of intellectual functioning in patients with Parkinson's disease (PD). PD patients and elderly control subjects were administered a neuropsychological test battery that included the complete WAIS-R or the S-M. Results indicated that the S-M was a reliable measure of IQ. The PD subjects' Verbal, Performance, and Full-Scale IQ scores were inferior to that of controls, regardless of test form. Adjustments for depression and age did not alter these results. PD patients with more severe disease scored lower on some visual-spatial measures. Verbal decrements among PD patients may relate to problems in verbal fluency, categorical thinking, and impaired retrieval of verbal material. PD patients may experience patterns of subtle cognitive changes that include deterioration of some specific abilities as the disease progresses.