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Dynamic Digital Biomarkers of Motor and Cognitive Function in Parkinson's Disease
Published on: July 24, 2019
Changes in motor subtype and risk for incident dementia in Parkinson's disease
Guido Alves1, Jan Petter Larsen, Murat Emre
1The Norwegian Center for Movement Disorders, Stavanger, Norway. algu@sir.no
Summary
Changes in Parkinson's disease motor symptoms, specifically developing postural instability and gait difficulty (PIGD), significantly increase dementia risk. Tremor-dominant (TD) patients only developed dementia after transitioning to PIGD.
Area of Science:
- Neurology
- Neuroscience
- Geriatrics
Background:
- Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms.
- Motor subtypes, such as tremor-dominant (TD) and postural instability gait difficulty (PIGD), may have different prognoses.
- The relationship between motor symptom progression and dementia development in PD is not fully understood.
Purpose of the Study:
- To investigate the temporal association between changes in motor symptom subtypes and the incidence of dementia in Parkinson's disease.
- To determine if specific motor subtypes or transitions between subtypes predict dementia risk.
Main Methods:
- Prospective cohort study of 171 non-demented Parkinson's disease patients.
- Classification of motor subtypes (TD, indeterminate, PIGD) at baseline, 4, and 8 years using the Unified Parkinson's Disease Rating Scale.
- Dementia diagnosis based on DSM-III-R criteria, clinical interviews, cognitive scales, and neuropsychological testing.
- Logistic regression analysis to assess the relationship between motor subtype transitions and dementia.
Main Results:
- Transitioning to the PIGD subtype, or having a persistent PIGD subtype, was strongly associated with a significantly increased odds ratio for dementia (OR 56.7 and 80.0, respectively).
- Patients with TD subtype at baseline did not develop dementia unless they transitioned to the PIGD subtype.
- A substantial proportion of PD patients developing PIGD experienced accelerated cognitive decline and a highly increased risk of subsequent dementia.
Conclusions:
- The development of postural instability and gait difficulty (PIGD) is a critical turning point associated with accelerated cognitive decline and a substantially elevated risk of dementia in Parkinson's disease.
- These findings suggest a potential shared or parallel neuropathology between PIGD and dementia in PD.
- Clinical monitoring of motor subtype progression may aid in predicting dementia risk in Parkinson's disease patients.
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