Research consent capacity varies with executive function and memory in Parkinson's disease.

Depression is associated with more rapid cognitive decline in Parkinson's disease (PD).The goal of this study was to examine the impact of the acute (8-week) and longer-term (24-week) antidepressant treatment on cognition in PD and to detail cognitive predictors of treatment response.Fifty-two depressed PD patients were enrolled in an NIH funded randomized-controlled trial of nortriptyline, paroxetine, and placebo.Neuropsychological testing was performed at baseline, and weeks eight and twenty-four.Higher baseline scores on measures of executive functioning, speed of processing, and verbal memory were associated with antidepressant response.Treatment responders did not exhibit larger gains in cognition than non-responders.Findings warrant replication.

Aims Investigate the relationship between global cognition and cognitive domain function and balance performance in a large sample of older people with cognitive impairment. Methods Three hundred and nine community-dwelling older people (mean age=82 years; 47% female) with cognitive impairment were recruited for the iFOCIS fall prevention randomised controlled trial. Baseline assessments completed before randomisation were used for analyses and included the Addenbrooke’s Cognitive Examination-III (ACE-III; global cognitive function) and its individual cognitive domains (attention; memory; verbal fluency; language; visuospatial ability) and executive function, further examined using the Frontal Assessment Battery (FAB). Balance performance was derived by averaging postural sway on floor and foam, maximal balance range (reverse z-score) and co-ordinated stability z-scores. With balance performance as the dependent variable, global cognition and each cognitive domain were entered into multivariate linear regression models. Results Mean (± standard deviation) ACE-III and FAB scores were 62.8±19.2 and 11.4±4.6 respectively. In linear regression analyses adjusted for covariates, global cognitive function and each cognitive domain were significantly associated with balance performance. Executive function (verbal fluency; β=-.248, p<0.001, adjusted R2=0.376) and visuospatial ability (β=-.250, p<0.001, adjusted R2=0.381) had the strongest and memory the weakest (β=-.119, p=0.018, adjusted R2=0.334) association with balance. Visuospatial ability remained significantly associated with balance performance when adjusted for attention, memory, language, verbal fluency and the FAB. Executive function (verbal fluency) remained significantly associated with balance when adjusted for attention, memory, language and visuospatial ability. Conversely, attention, memory, and language did not withstand adjustment for visuospatial ability or executive function. Conclusions Poorer global cognition and performance in each cognitive domain were associated with poorer balance performance in this large sample of community-dwelling older people with cognitive impairment. Visuospatial ability and executive function were independently associated with balance, highlighting the role higher-level cognitive processes and spatial perception and processing play in postural control.

The purpose of this study was to examine the relationship between signal hyperintensities--a probable marker of underlying pathology--on T2-weighted magnetic resonance brain scans and neuropsychological test findings in elderly depressed and normal subjects. Elderly subjects with a DSM-III-R diagnosis of major depression (N=41) and normal elderly comparison subjects (N=38) participated in a magnetic resonance imaging study (1.0-T) of signal hyperintensities in periventricular, deep white matter, and subcortical gray matter. Hard copies of scans were rated in random order by research psychiatrists blind to diagnosis; the modified Fazekas hyperintensity rating scale was used. Cognitive performance was independently assessed with a comprehensive neuropsychological battery. Clinical and demographic differences between groups were assessed by t tests and chi-square analysis. Relationships between neuropsychological performance and diagnosis and hyperintensities and their interaction were analyzed by using analysis of covariance, with adjustment for age and education. Elderly depressed subjects manifested poorer cognitive performance on several tests than normal comparison subjects. A significant interaction between hyperintensity location/severity and presence/absence of depression on cognitive performance was found: depressed patients with moderate-to-severe deep white matter hyperintensities demonstrated worse performance on general and delayed recall memory indices, executive functioning and language testing than depressed patients without such lesions and normal elderly subjects with or without deep white matter changes. Findings validate cognitive performance decrements in geriatric depression and suggest possible neuroanatomic vulnerabilities to developing particular neuropsychological dysfunction in depressed subjects.

Objective The Dementia Rating Scale-2 (DRS-2) is recommended for assessing global cognition in Parkinson’s disease (PD) by the Movement Disorder Society. However, empirical evidence is limited regarding the degree to which the DRS-2 corresponds to traditional neurocognitive domains (i.e., construct validity) in PD. Thus, this study aims to determine the construct validity of the DRS-2 in a non-demented sample of PD patients. Method Patients with PD (n = 359; mean age = 64.50 ± 8.53, education = 14.97 ± 2.73, disease duration = 8.48 ± 4.87, UPDRS Part III motor scale scores = 25.23 ± 10.17) completed the DRS-2 as part of a comprehensive neuropsychological assessment consisting of attention/working memory, executive function, language, delayed recall, and visuoperceptual-spatial skills.Bootstrapped bias-corrected Spearman rho’s correlations andhierarchical linear regressions were performed to examine construct validity of DRS-2 total and subscale scores. Results Speeded measures of set-shifting, rapid word generation to letter and semantic cues, and simple visuoperceptual skills largely accounted for variance in DRS-2 total scores. Most DRS-2 subscale scores showed weak relationships with theoretically related neuropsychological measures. Conclusions DRS-2 total scores reflect impairment across a range of cognitive domains (i.e., executive, language, and visuoperception), while DRS-2 subscale scores have limited construct validity. Together, the DRS-2 does not appear to have utility beyond screening for global cognition in PD.

Domain specific cognitive impairment in Parkinson’s patients with mild cognitive impairment

Purpose People with Parkinson’s disease (PD) can develop cognitive and physical impairments. There is limited evidence on the association between executive function and physical function in people with PD. Objective We aimed to investigate the association between the executive and physical functions in people with Parkinson’s disease (PD) by comparing healthy controls. Method Thirty-three patients diagnosed with PD and 33 healthy controls were included in the study. PD group was divided into two subgroups according to their scores on executive tests as high performers (PD-HPs; n = 17) and low performers (PD-LPs; n = 16). The severity of motor symptoms disease severity, executive function, global cognitive function, reaction time, hand function, functional capacity, physical activity, and balance confidence was assessed by the validated instruments. Results The PD group had less physical function and executive function compared to healthy controls (p < 0.05). The PD-LPs group had less physical and cognitive function than the PD-HPs group (p < 0.05). The executive functions were significantly correlated with almost all variables in both people with PD and healthy people, and correlations were moderate to strong (p < 0.05). However, the correlation coefficients were relatively higher in people with PD compared to healthy controls. Conclusion There was a significant association between executive and physical function in people with PD. Future studies should be conducted to determine whether the treatment of one of these dysfunctions affects the other.

Mild cognitive impairment is common in Parkinson's disease patients with normal Mini-Mental State Examination (MMSE) scores

Improved cognition while cycling in Parkinson’s disease patients and healthy adults

Deficit in specific cognitive domains associated with dementia in Parkinson’s disease

The literature on cognitive markers in preclinical AD is reviewed. The findings demonstrate that impairment in multiple cognitive domains is typically observed several years before clinical diagnosis. Measures of executive functioning, episodic memory and perceptual speed appear to be most effective at identifying at-risk individuals. The fact that these cognitive domains are most implicated in normal cognitive aging suggests that the cognitive deficit observed preclinically is not qualitatively different from that observed in normal aging. The degree of cognitive impairment prior to the diagnosis of Alzheimer's disease (AD) appears to generalize relatively well across major study characteristics, including sample ascertainment procedures, age and cognitive status of participants, as well as time to diagnosis of dementia. In episodic memory, there is evidence that the size of the preclinical deficit increases with increasing cognitive demands. The global cognitive impairment observed is highly consistent with observations that multiple brain structures and functions are affected long before the diagnosis of AD. However, there is substantial overlap in the distribution of cognitive scores between those who will and those who will not be diagnosed with AD, hence limiting the clinical utility of cognitive markers for early identification of cases. Future research should consider combining cognitive indicators with other types of markers (i.e. social, somatic, genetic, brain-based) in order to increase prediction accuracy.

Parkinson's disease (PD) is a neurological disorder characterized by motor disturbances, neuropsychological symptoms and cognitive changes, including cases of dementia. The most frequently described cognitive changes in these patients involve executive and visuospatial functions, which are very important for the execution of daily life activities.ObjectiveTo compare different tests used to examine visuospatial functions in patients with PD.MethodsThirty-five patients (21 women) with PD symptoms (medicated and “on”) and mean schooling of 5.5±4.2 years were examined using the following tests: Mini-Mental State Examination (MMSE), Dementia Rating Scale (DRS), Scales of Outcomes of Parkinson's Disease (SCOPA-COG), Hooper Visual Organization Test (HVOT), Judgment of Line Orientation, Form V (JLO), and Clock drawing task – CLOX (1 and 2).ResultsThe mean MMSE score was 24.8±3.03and 54.8% of the patients performed correctly in the copy of a pentagon drawing, with a medium-level performance in most tests. Good correlations were detected between JLO versus SCOPA Assembling patterns (0.67), JLO versus HVOT (0.56), JLO versus CLOX2 (0.64), SCOPA Figure Composition versus HVOT (0.54), CLOX1 versus CLOX2 (0.43), and DRS Construction versus CLOX2 (0.42).DiscussionAlthough correlations were detected, not all were strong, probably because the tests employed do not measure solely visuospatial functions, but also other skills such as attention, motor ability and executive functions. A limitation of the present study was the lack of a control group for the establishment of adequate standards for this population.

Cognitive difficulties are well documented in developmental dyslexia but they present a challenge to dyslexia theory. In this paper, the Model of the Control of Action is proposed as a theoretical explanation of how and why deficits in both automaticity and executive abilities are apparent in the cognitive profiles of dyslexia and how these deficits might relate to literacy difficulties. This theoretical perspective is used to consider evidence from different cognitive domains. The neuroanatomical underpinnings of automaticity and executive abilities are then discussed in relation to the understanding of dyslexia. Links between reading, writing, and executive function are considered. The reviewed evidence suggests that dyslexia theory should consider an interaction between procedural learned behaviour (automaticity) and higher-order (executive) abilities. The capacity to handle environmental interference, develop and engage adaptive strategies accordingly, and plan actions all require interactions between the cerebellum and the prefrontal cortex (PFC). Difficulties in these areas might explain both impairments in the cumulative development of literacy skills in childhood and general task management in everyday life in adulthood. It is suggested that improved measures are required to assess this cerebellar–PFC interaction and to allow early identification of future literacy difficulties, allowing implementation of timely interventions and reasonable adjustments.

Impact of mild cognitive impairment on outcome following deep brain stimulation surgery for Parkinson's disease.

Intraindividual variability in neurocognitive speed: A comparison of Parkinson's disease and normal older adults

Intraindividual variability increases with age, but the relative strength of association with cognitive domains is still unclear. The objective of this study was to examine the relation between cognitive domains and the shape and spread of response time (RT) distributions as indexed by intraindividual standard deviation (ISD), and ex-Gaussian parameters (μ, σ, τ). Healthy adults (40 young [aged 18-30 years], 40 young-old [aged 65-74 years], and 41 old-old [aged 75-85 years]) completed neuropsychological testing and a touch-screen attention task from which ISD and ex-Gaussian parameters were derived. The relation between RT performance and cognitive domains (memory, processing speed, executive functioning) was examined with structural equation modeling (SEM), and the predictive power of RT distribution indices over age was investigated with linear regression. ISD, μ, and τ, but not σ, showed a linear increase with age group. An SEM showed that independent of age, τ was most strongly associated with executive functioning, while μ exhibited less critical associations. Linear regression indicated that μ and τ explained a significant portion of variance in processing speed and executive ability in addition to age group. Memory was more parsimoniously predicted by age, without any significant contribution of ex-Gaussian parameters. The findings suggest that exceptionally slow responses convey attention lapses through wavering of cognitive control, which strongly correspond to executive functioning tests. General slowing and extremely slow responses predicted processing speed and executive performance beyond age group, indicating that RT metrics are sensitive to differences in cognitive ability. (JINS, 2018, 24, 456-465).