Subjective Cognitive Complaints in Parkinson's Disease: A Systematic Review and Meta‐Analysis

Abstract

BackgroundSubjective cognitive complaints (SCCs) in Parkinson's disease (PD) are reported frequently, but their prevalence and association with changes on objective testing are not fully known.ObjectiveWe aimed to determine the prevalence, clinical correlates, and predictive value of SCCs in PD.MethodsWe conducted a systematic review and meta‐analysis. From 204 abstracts, we selected 31 studies (n = 3441 patients), and from these, identified the prevalence, clinical features, associations with neuropsychiatric symptoms, and predictive values of SCCs in PD.ResultsThe meta‐analysis showed an SCC prevalence of 36%. This prevalence, however, was significantly moderated by study heterogeneity regarding female sex, disease severity, levodopa equivalent daily dosage, exclusion from the overall sample of patients with objective cognitive impairment, and measurement instrument. SCC prevalence did not differ between de novo and treated PD patients. SCCs were weakly and negligibly associated with cognitive changes on objective testing in cross‐sectional studies. However, in cognitively healthy patients, SCCs had a risk ratio of 2.71 for later cognitive decline over a mean follow‐up of 3.16 years. Moreover, SCCs were moderately related to co‐occurring symptoms of depression, anxiety, or apathy and were more strongly related to these neuropsychiatric symptoms than objective cognitive functioning.ConclusionOur analyses suggest that SCCs in patients with and without objective cognitive impairment are frequent, occurring in more than one third of PD patients. Establishing uniform measurement instruments for identifying PD‐related SCCs is critical to understand their implications. Even in cases lacking evidence of objective cognitive impairment and where SCCs might reflect underlying neuropsychiatric symptoms, the possibility of later cognitive deterioration should not be excluded. Therefore, SCCs in PD patients warrant close monitoring for opportunities for targeted and effective interventions. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Cognitive Symptoms in Cross-Sectional Parkinson Disease Cohort Evaluated by Human-in-the-Loop Machine Learning and Natural Language Processing

“…subjective cognitive complaint frequency can be up to 50% higher compared with questionnaires with several specific examples such as "Do you often forget appointments?" 24 To our knowledge, our study examining the frequency and nature of subjective cognitive problems without prompting individuals about specific cognitive domains is unique.…”

“… 28 A recent systematic review and meta-analysis found wide ranges of frequency of subjective cognitive complaints based on how the question was asked. For example, when asked with a global question “Do you feel that you have a declining memory?” subjective cognitive complaint frequency can be up to 50% higher compared with questionnaires with several specific examples such as “Do you often forget appointments?” 24 To our knowledge, our study examining the frequency and nature of subjective cognitive problems without prompting individuals about specific cognitive domains is unique.…”

“…There is little known from the prior literature regarding demographic and clinical correlates of SCC; however, a meta-analysis also found lower rates of SCC in more advanced disease and postulated changing priorities as an explanation. 24 Higher education was positively associated with reporting of memory symptoms as a bothersome problem. Considering prior literature on objective cognitive performance, there are data to suggest that higher education may be protective against cognitive decline because of cognitive reserve.…”

Parkinson’s Disease Dementia Patients: Expression of Glia Maturation Factor in the Brain

“…Men are about 1.5 time more prone to develop PD than women [ 4 ]. PD patients show cognitive impairment [ 2 , 5 , 6 , 7 ]. About 60 to 80% of PD patients may eventually show Parkinson’s disease dementia (PDD) [ 8 ].…”

Cognitive disorders in Parkinson's disease

“…However, several other clinical manifestations can significantly complicate the course of the disease. These are the so-called non-motor symptoms, which include emotional, cognitive, autonomic, and sensory disorders, as well as psychotic [1,2,3]. According to DSM-IV criteria (American Psychiatric Association, 1994), dementia in PD can be presented as a progressive memory impairment syndrome in the absence of aphasia, apraxia, or agnosia.…”