Apathy in Parkinson's disease: A systematic review and meta‐analysis

Abstract

Apathy is a frequently reported neuropsychiatric symptom in Parkinson's disease (PD), but its prevalence and clinical correlates are debated. We aimed to address these issues by conducting a systematic review and meta-analysis. Embase, Medline/PubMed, and PsychINFO databases were searched for relevant studies. Data were extracted by two independent observers, using predefined extraction forms tailored specifically to the research question. From 1,702 titles and abstracts, 23 studies were selected. Meta-analysis showed a prevalence of apathy in PD of 39.8% (n = 5,388, 905% CI 34.6-45.0%). Apathy was associated with higher age (3.3 years, 95% CI = 1.7-4.9), lower mean Mini-Mental State Evaluation (MMSE) score (-1.4 points, 95% CI = -2.1 to -0.8), an increased risk of co-morbid depression (relative risk [RR] = 2.3, 95% CI = 1.9-2.8), higher Unified Parkinson's Disease Rating Scale (UPDRS) motor score (6.5 points, 95% CI = 2.6-10.3), and more severe disability (Hedges-G = 0.5, 95% CI = 0.3-0.6). Half of the patients with apathy had concomitant depression (57.2%, 95% CI = 49.4-64.9%), and this estimate was similar after exclusion of patients with cognitive impairment (52.5%, 95% CI = 42.2%-62.8%). In conclusion, we found that apathy affects almost 40% of patients with PD. Several factors influence reported prevalence rates, contributing to the considerable heterogeneity in study results. Half of patients with apathy do not suffer from concomitant depression or cognitive impairment, confirming its status as a separate clinical syndrome in PD. The pervasiveness of apathy in PD warrants research into its treatment, although different underlying pathophysiological mechanisms may require different treatment strategies. Treatment of apathy could improve patient quality of life, reduce caregiver burden, alleviate disability by increasing motivation for self-care, and reduce cognitive impairment by improving executive functioning.

Apathy in Parkinson�s disease: differences between caregiver�s report and self-evaluation

“…Several factors may account for these differences; in particular, our subjects showed a longer disease duration, older age, more advanced disease stage and greater motor impairment, and scored lower on cognitive tests. Most of these factors have been shown to be associated with the frequency of apathy in PD (den Brok et al, 2015). This insight is further supported by our finding of significant correlations between AES scores (both SE and CR) and those recorded on the UPDRS III and H-Y scales, and, at least in the SE version, also with the MMSE and FAB scores.…”

“…In our sample, apathy was found to affect the majority of the patients, as shown both by selfratings and informant ratings. The percentage of apathetic subjects was higher than that reported in the literature (den Brok et al, 2015), and the AES-SE scores were higher than those reported in the study by Santangelo et al (2014) in de novo untreated Italian PD patients. Several factors may account for these differences; in particular, our subjects showed a longer disease duration, older age, more advanced disease stage and greater motor impairment, and scored lower on cognitive tests.…”

“…According to a recent metaanalysis report, apathy affects 16 to 62% of patients with PD, with an average prevalence of 40%, depending on the sample population, diagnostic criteria and evaluation tools. The Authors showed that apathy is associated with higher age, lower mean Mini-Mental State Evaluation (MMSE) score, increased risk of comorbid depression, higher Unified Parkinson's Disease Rating Scale (UPDRS) motor subscale score, and more severe disability (den Brok et al, 2015). The diagnosis of apathy is challenging since many of its features overlap with symptoms commonly associated with PD, e.g., bradyphrenia, fatigue, etc.…”

Differential impact of behavioral, social, and emotional apathy on Parkinson's disease

“…Apathy, a disorder of motivation characterized by reduced self‐initiated goal‐directed behavior,1 is very common in Parkinson's disease (PD) and associated with diminished quality of life 2, 3, 4. Theoretical accounts5 and new evidence6 suggest that rather than being a unitary construct, apathy is multidimensional, involving behavioral, cognitive, executive, social, and emotional domains.…”

Apathy in Mild Parkinson’s Disease: Neuropsychological and Neuroimaging Evidence

“…The prevalence of apathy in PD varies from 17-70%, depending on the assessment procedures and the characteristics of the population [2,[5][6][7][8]. A recently published systematic review, and meta-analysis found that apathy affects about 40% of patients with PD [9] Several studies have indicated that apathy is correlated with cognitive impairments in patients with PD [4,7,[10][11][12][13][14][15][16][17][18]. For instance, a study investigated cognitive abilities in a patient group (23 with apathy and 25 without apathy) using the Apathy Evaluation Scale (AES) [19] and digit span [20], the Delis-Kaplan Executive Function Test [21], the California Verbal Learning Test [22] and the Wisconsin Card Sorting Test (WCST) [23].…”