Subjective cognitive Complaints in early Parkinson's disease patients with normal cognition are associated with affective symptoms

Abstract

Subjective cognitive complaints (SCC) and affective symptoms are highly prevalent in Parkinson's Disease (PD). In early PD, SCC prevalence and its affective correlates, using recommended Movement Disorders Society (MDS) Level II Criteria to define the underlying cognitive impairment, has not been previously explored. Methods: We recruited 121 participants with early PD from two tertiary hospitals in Singapore. The presence of SCC was defined using a Non-Motor Symptoms Scale Domain-5 Score ≥1. Comprehensive neuropsychological testing was conducted with Mild Cognitive Impairment (PD-MCI) defined using recommended MDS Level II Criteria. Affective symptoms were assessed using the Hospital Anxiety Depression Scale (HADS), Geriatric Depression Scale (GDS) and Apathy Scale (AS). Analysis using multivariable linear regression model was performed. Results: In our early PD cohort, SCC prevalence independent of underlying cognitive status was 38.8%. Prevalence of SCC in cognitively impaired and cognitively normal participants was 10.7% and 28.1% respectively (р = 0.241). In cognitively normal PD participants, multivariable linear regression analysis revealed that SCC was significantly associated with anxiety (β = 0.28, 95% CI = 0.09-0.79, p = 0.014), depression (β = 0.31, 95% CI = 0.10-0.59, p = 0.006) and apathy (β = 0.32, 95% CI = 1.15-5.98, p = 0.004). Such an association was not found in cognitively impaired PD participants. Conclusion: SCC is highly prevalent even in early PD. Its implications in early PD differ depending on underlying cognitive status. SCC in cognitively impaired participants underestimates the true prevalence of PD-MCI. In contrast, SCC in cognitively normal participants is suggestive of an underlying affective disorder.

Parkinson disease-associated cognitive impairment

“…The emerging concept of SCD 6 is also arising from the field of AD and has been a novel focus of PD research in the past few years. In one of the first studies assess ing whether subjective memory complaints in patients with de novo PD (defined as either newly diagnosed patients or patients not receiving dopaminergic medica tions) could predict cognitive decline, 30.3% of patients complained of memory issues and were more likely to develop MCI within 2 years of followup compared with patients who did not complain of memory issues 34 ; sub sequent studies have supported this 35 , although several factors, such as affective symptoms 36 , may contribute to progression to MCI (see Diagnosis, screening and prevention, below).…”

Disease progression in Parkinson‘s disease patients with subjective cognitive complaint

“…Recent studies have validated the association between PD‐SCC and depression, 28 , 29 , 30 and increased PD‐SCC severity is associated with increasing depression scores. 11 However, the results might be attributed to the fact that PD patients with subthreshold depression tend to overestimate their cognitive deficits. 1 , 2 , 31 Furthermore, in our study, it is worth noting that PD‐SCC patients, not PD‐MCI patients, had significantly greater progression in depression than the NC group.…”

“…We found higher BDI scores in the PD‐SCC group than in the PD‐NC group at baseline. Recent studies have validated the association between PD‐SCC and depression, 28–30 and increased PD‐SCC severity is associated with increasing depression scores 11 . However, the results might be attributed to the fact that PD patients with subthreshold depression tend to overestimate their cognitive deficits 1,2,31 .…”

“…The prevalence of SCC in nondemented PD patients is estimated to be between 16.3% and 38.8% 8–11 . Several studies have been performed on the association between SCC and objective cognitive impairment or subsequent cognitive decline in PD patients.…”

“…The prevalence of SCC in nondemented PD patients is estimated to be between 16.3% and 38.8%. 8 , 9 , 10 , 11 Several studies have been performed on the association between SCC and objective cognitive impairment or subsequent cognitive decline in PD patients. A 2‐year follow‐up study reported no significant changes in neuropsychological assessments between nondemented patients with and without SCC.…”