Subjective cognitive complaints in cognitively unimpaired Parkinson’s disease: Associations with affective burden, motor severity, and awareness-related processes

Abstract

Subjective cognitive complaints (SCC) are frequent in Parkinson’s disease (PD), but their significance in cognitively unimpaired individuals remains uncertain. To investigate the frequency of SCC in cognitively unimpaired PD patients and examine associations with objective cognition, mood symptoms, and anosognosia. In this cross-sectional study, 74 PD patients with preserved cognitive performance based on the Addenbrooke’s Cognitive Examination–Revised (ACE-R) were included. SCC were assessed using the Prospective and Retrospective Memory Questionnaire (PRMQ-10). Mood symptoms were measured with the Hospital Anxiety and Depression Scale (HADS). Associations were analyzed using nonparametric tests, correlations, and multivariable linear regression. Anosognosia was estimated using a subjective–objective discrepancy index. SCC were present in 36 participants (48.6%). SCC status was not associated with ACE-R total or memory scores. SCC+ participants showed higher affective symptom burden and greater motor severity. PRMQ-10 scores correlated with HADS measures, particularly depressive symptoms. In adjusted models, SCC status showed a modest positive association with ACE-R total scores. No descriptive evidence of systematic discrepancy between subjective and objective memory measures was observed. SCC were highly prevalent in cognitively unimpaired PD and were more strongly associated with affective burden and motor severity than with objective cognitive performance.