Cognitive Functions in Major Depression and Parkinson Disease

Abstract

Major depression in patients with PD is associated with significant deficits on specific cognitive tasks. While some of these deficits may be explained by the presence of major depression, frontal lobe-related cognitive impairments may result from an interaction between neuropathologic factors in PD and the mechanism of major depression.

A dopamine agonist, pramipexole, and cognitive functions in Parkinson's disease

“…To generate words in these tasks, subject must plan and initiate a systematic search of memory (15). Performance in letter fluency test is reported both as intact (16) and impaired in PD patients (17). Compared to controls, our PD patients showed significantly inferior performance in this task.…”

Cognitive and neuroanatomical correlates of neuropsychiatric symptoms in Parkinson's disease: A systematic review

“…Several studies have demonstrated an association between depression and cognitive impairments in PD patients [22][23][24][25][26][27][28][29][30]. There are, however, a few other studies that did not detect a significant association between depression and variance in cognitive deficit in PD (See table 1) [31][32][33][34].…”

“…In terms of executive dysfunction, several studies have reported that patients with depression performed significantly lower than non-depressed patients on tests of executive function including the Wisconsin Card Sort Test (WCST) [35], Controlled Word Association Test-FAS [36], Trail Making Test (TMT) (A and B) [37], Verbal Fluency, Abstract Reasoning, Design Fluency Test (Free condition) [38] and the Symbol Digit Modalities [39], [25,28,30] . Other studies have also demonstrated that depressed PD patients had lower scores relative to non-depressed PD patients using a variety of executive tasks e.g.…”

“…Letter Fluency, Abstract Reasoning and Card Sorting Test [22], Category Fluency Test and TMT [29], setshifting and response inhibition [40], Frontal Assessment Battery and Stroop test [27]. As for deficits in other cognitive domains, earlier studies have reported an association between depression and poorer scores on tasks of attention (assessed by a subtest of the Dementia Rating Scale and Digit Span Forward) [25,26], short-term memory (measured by Digit Span Forward and Backward) [30], and memory which was assessed by the Word-list recall and recognition test [22], Hopkins Verbal Learning Test [24,41], a subtest of the Dementia Rating Scale [26] and the Pattern Recognition Memory Task [29]. In addition, another study indicated a relationship between depression and poorer performance on a range of cognitive tasks including those testing executive function (Trail Making Test), memory (Rey Auditory Verbal Learning Test) and visuospatial skills (Rey-Osterreith Complex Figure Test) [42].…”

CBT for the treatment of depression in Parkinson’s disease: a promising nonpharmacological approach

“…Difficulties with memory, attention, and language are also common in PD and are frequently aggravated by depression [8,59,60,61,62]. This widespread cognitive impairment has been noted despite the absence of clinically significant cognitive decline [8].…”