Non-motor symptoms questionnaire-based profiles in early-stage dementias: A prospective cohort study

Background Current knowledge regarding the nature and prevalence of non-motor symptoms across different types of dementia is limited. While Alzheimer's disease (AD), behavioral variant frontotemporal dementia (bvFTD), and dementia with Lewy bodies (DLB) are primarily characterized by cognitive and motor symptoms, several other features such as non-motor symptoms are also known to occur in all these conditions. Objective To assess non-motor symptoms in early-stage dementia and characterize symptom profiles across different neurodegenerative dementia diseases. Methods A total of 64 AD, 38 bvFTD, and 17 DLB early-stage patients, along 63 cognitively healthy controls (HC), were prospectively recruited from Kuopio and Oulu University Hospitals. Non-motor symptoms were evaluated using the Non-Motor Symptoms Questionnaire (NMSQ), focusing on gastrointestinal, neuropsychiatric, cognitive, sleep-related and sensory-motor domains within three timeframes prior to the baseline visit. Results DLB patients exhibited the highest prevalence of non-motor symptoms across all domains. bvFTD and AD patients did not show disease group specific symptoms, but apathy and paranoidal thoughts appeared earlier in bvFTD than AD or DLB. Diplopia was reported by 14% of DLB patients (Fisher exact test, p = 0.035) one year before diagnosis. Neuropsychiatric and cognitive symptoms were more frequent in all dementia groups compared to HC (Fisher exact test, p < 0.01). Conclusions Non-motor symptom profiles differ among these dementia subtypes even at early stages, suggesting their potential utility as early disease-specific indicators.