Reliability and Validity of the Subjective Cognitive Complaints Questionnaire for Parkinson’s Disease (SCCQ-PD)

Fasting glucose variability and risk of dementia in Parkinson's disease: a 9-year longitudinal follow-up study of a nationwide cohort

Background

Diabetes is associated with an increased risk of Parkinson's disease dementia (PDD); however, it is unknown whether this association is dependent on continuous hyperglycemia, hypoglycemic events, or glycemic variability. We aimed to investigate the relationship between visit-to-visit fasting glucose variability and PDD development in patients with Parkinson's disease (PD).

Methods

Using data from the Korean National Health Insurance Service, we examined 9,264 patients aged ≥40 years with de novo Parkinson's disease (PD) who underwent ≥3 health examinations and were followed up until December 2019. Glucose variability was measured using the coefficient of variation, variability independent of the mean, and average real variability. Fine and Gray competing regression analysis was performed to determine the effect of glucose variability on incident PDD.

Results

During the 9.5-year follow-up period, 1,757 of 9,264 (19.0%) patients developed PDD. Patients with a higher visit-to-visit glucose variability had a higher risk of future PDD. In the multivariable adjusted model, patients with PD in the highest quartile (subdistribution hazard ratio [SHR] = 1.50, 95% CI 1.19 to 1.88), quartile 3 (SHR = 1.29, 95% CI 1.02 to 1.62), and quartile 2 (SHR = 1.30, 95% CI 1.04 to 1.63) were independently associated with a higher risk of PDD than those in the lowest quartile.

Conclusion

We highlighted the effect of long-term glucose variability on the development of PDD in patients with PD. Furthermore, our findings suggest that preventive measures for constant glucose control may be necessary to prevent PDD.

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

BACKGROUND

Subjective 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.

OBJECTIVE

We aimed to determine the prevalence, clinical correlates, and predictive value of SCCs in PD.

METHODS

We 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.

RESULTS

The 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.

CONCLUSION

Our 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.

Subjective Cognitive Complaints in Cognitively Normal Patients With Parkinson's Disease: A Systematic Review

Subjective cognitive complaints (SCCs) refer to self-perceived cognitive decline and are related to objective cognitive decline. SCCs in cognitively normal individuals are considered a preclinical sign of subsequent cognitive impairment due to Alzheimer's disease, and SCCs in cognitively normal patients with Parkinson's disease (PD) are also gaining attention. The aim of this review was to provide an overview of the current research on SCCs in cognitively normal patients with PD. A systematic search found a lack of consistency in the methodologies used to define and measure SCCs. Although the association between SCCs and objective cognitive performance in cognitively normal patients with PD is controversial, SCCs appear to be predictive of subsequent cognitive decline. These findings support the clinical value of SCCs in cognitively normal status in PD; however, further convincing evidence from biomarker studies is needed to provide a pathophysiological basis for these findings. Additionally, a consensus on the definition and assessment of SCCs is needed for further investigations.