Table 1. Study characteristics.

First author, publication year, study design	Number of participants, age, sex (male to female percentage), country	Objective	Sedentary behavior/ physical inactivity (exposure and length of assessment)	Non-motor symptoms studied (including domains where applicable)/tools used for assessment	Results
Ellingson et al., 2019 [15] Cross-sectional	52 participants, mean age 67.8 ± 7.9 years, 56% males, 44% females, USA	To investigate the relationships between sedentary behavior and markers of quality of life including a subscale for cognitive function in PD	Objectively measured sedentary time using activPAL and Actigraph accelerometers. 4 valid days (≥10h/d of accelerometer wear time), including 1 weekend day included in the analysis. Self-reported sedentary time measured using Sedentary Behavior Questionnaire (SBQ).	Cognition (memory, executive function, and processing speed): PDQ-39 for quality of life with subscale for cognitive function. The cognitive domain consists of 4 items (items 30–33 on the PDQ-39).	Higher amounts of objectively measured sedentary time accumulated in prolonged bouts were reported to be associated with worse scores on the PDQ summary index (ρ = 0.34; P < .05) and on subscales of mobility, cognition, and communication (ρrange = 0.32–0.41; P < .05). Higher amounts of self-reported time spent watching television were associated with lower PDQ index score (ρ = 0.35; P < .05) as well as for subscales of mobility, emotion, social, cognitive, and communication (ρrange = 0.29–0.39; P < .05).
van Uem et al., 2018 [28] Cross sectional	47 participants, median age 70 [65–74] years, 74% males, 26% females, United Kingdom	To investigate the association between amount of physical activity, severity of depression, cognitive function and quality of life in Parkinson’s disease	DynaPort MiniMod accelerometer was used to objectively measure movement data (which includes sedentary behavior called ‘sedentary episodes’ in this study–lying/sitting. 3 consecutive days of accelerometer wear.	Depression: Geriatric Depression Scale, Cognition: Mini-Mental State Examination (MMSE) for cognitive impairment, German version of the Parkinson’s Disease Questionnaire (PDQ)-39 to assess overall quality of life.	Prolonged sedentary bouts were associated with lower quality of life measured with PDQ-39-measured health-related quality of life. Depression measured by Geriatric Depression Scale reported to be a significant predictor of overall quality of life measured with the German version of the PDQ-39, with sedentary bout length being a modifier. Depression (standardized Beta 0.32; p = 0.009), MMSE (standardized Beta -0.25; p = 0.02) alongside motor scores and steps explained 60.5% variance in PDQ-Activities of Daily Living (ADL). Similarly, depression (standardized Beta 0.59; p<0.01), mean sedentary bout length (standardized Beta (0.42; p<0.01), and age explained 60.2% of the variance in PDQ-ADL.
Jones et al., 2020 [29] Longitudinal cohort study	307 participants, mean age 61 ± 9.9 years, 65.8% males, 34.2% females, USA	To investigate the association between participating in everyday physical activity and clinical cognitive outcomes	Subjective measurement of physical (in)activity using self-report Physical Activity Scale for the Elderly (PASE). Follow up for 3 years.	Cognition: memory (Hopkins Verbal Learning Test-Revised), visuospatial abilities (Judgment of Line Orientation), processing speed-attention (Symbols Digits Modalities Test), and language/semantic fluency (Animal Fluency).	Cognitive status was associated with household physical (in)activity. Engaging in less physically-demanding household activities (Beta -0.38; p = 0.002) was associated with a higher risk of PD-related mild cognitive impairment or dementia.
Timblin et al., 2022 [30] Longitudinal cohort study	487 participants, mean age 61.1 ± 9.7 years, 65.1% males, 34.9% females, USA	To investigate the long-term role physical activity between depressive symptoms and cognition in individuals with Parkinson’s disease	Subjective measurement of physical (in)activity with self-report Physical Activity Scale for the Elderly (PASE). Follow up for 5 years.	Cognition: memory (Hopkins Verbal Learning Test-Revised), visuospatial abilities (Judgment of Line Orientation), processing speed-attention (Symbols Digits Modalities Test), and language/semantic fluency (Animal Fluency), and executive function/working memory (Letter-Number Sequencing). Depression: Geriatric Depression Scale-Short Form.	Results suggest that physical activity may be a mediator between depression and cognitive functioning in individuals diagnosed with PD. Depression is more likely to be associated with inactivity in household activities (Beta -0.52; p <0.01), which is indirectly linked to cognitive decline (Beta -0.63; p = 0.017).
Troutman et., 2020 [33] Cross-sectional study	17 participants, mean age 65.1 years, 82% males, 18% females, USA	To investigate the relationship between sedentary time and cognitive performance in individuals with mild-to-moderate Parkinson’s disease	Objective measurement of sedentary behavior using Sensewear pro armband. Percent of waking hours spent sedentary was derived. 72 hours of accelerometer wear.	Cognition (memory, working memory, verbal fluency, and attention): Parkinson’s Disease-Cognitive Rating Scale (PD-CRS) with average of the memory composite and attention scores to create a measure of global cognition, and a computerized task-switching paradigm to measure cognitive flexibility.	The percentage of awake time spent in sedentary activities was negatively associated with attention (Beta = -14.20; p = 0.03), after controlling for moderate-to-vigorous physical activity. The associations were not significant for other cognitive domains.
Sulzer et al., 2021 [31] Longitudinal cohort study	20 participants, median age 67.5 [44–80], 65% males, 35% females, Germany	To investigate the long-term impact of sedentary behavior and cognitive impairment in the home environment and its association to sickness and death in PD	DynaPort Minimod accelerometer was used for objective measurement of sedentary behavior (lying and sitting periods were combined and defined as sedentary behavior). 4.3 years follow up, accelerometer was worn for 72 hours at baseline.	Cognition (memory, verbal fluency, visuospatial task, working memory and attention): Parkinson Neuropsychometric Dementia Assessment (PANDA). Depression: Geriatric Depression Scale (GDS)	Longer sedentary mean bout length (p = 0.02) and cognitive impairment (p<0.01) were associated with health-related study attrition due to sickness and death in PD. Depression was weakly associated with predicted future dropout (Beta 0.13; p = 0.05).
Prusynski et al., 2022 [32] Prospective observational study	25 participants, mean age 69.0 ± 6.0 years, sex not specified, USA	To examine the association between sleep and physical activity in PD and healthy older adults	Objective measurement of sedentary behavior, physical activity and sleep using Fitbit Charge HR activity monitor. 14 days of monitor wear.	Sleep: Total minutes of nighttime sleep. Number of nighttime awakenings (NWAK). Wake time after sleep onset (WASO). Total minutes of daytime sleep. Total number of daytime nap count.	Each additional 30 minutes of nighttime sleep was associated with 25 fewer sedentary minutes in people with PD (Beta -25; p<0.01).