Simple Test of Manual Dexterity Can Help to Identify Persons at High Risk for Neurodegenerative Diseases in the Community

Abstract

Background: Early identification of individuals at high risk of developing neurodegenerative diseases is essential for timely preventive intervention. However, simple methods that can be used for risk assessment in general practice are lacking.

Methods: Within the population-based Rotterdam Study, we used the Purdue Pegboard Test (PPT) to assess manual dexterity in 4,856 persons (median age 70 years, 58% women) free of parkinsonism and dementia between 2000 and 2004. We followed these persons until January 1, 2012 for the onset of neurodegenerative diseases (defined as first diagnosis of parkinsonism or dementia). We determined the association of PPT scores with incident neurodegenerative disease, adjusting for age, sex, study cohort, level of education, smoking, preferred hand, parental history, memory complaints, and Mini-Mental State Examination. Furthermore, we determined the incremental predictive value of PPT, expressed as change in risk classification and discrimination.

Results: During follow-up (median 9.2 years), 277 participants were diagnosed with a neurodegenerative disease (227 with dementia and 50 with parkinsonism). Lower PPT scores were associated with higher risk of incident neurodegenerative diseases (hazard ratio [HR] = 1.28, 95% confidence interval [CI]: 1.18-1.41) and improved discrimination of incident neurodegenerative diseases. We also observed significant associations of PPT scores separately with incident dementia (HR = 1.25; 95% CI: 1.14-1.39]) and incident parkinsonism (HR = 1.41; 95% CI: 1.19-1.67).

Conclusions: A rapid, nonlaboratory test of manual dexterity may help to identify persons at high risk for neurodegenerative diseases. This highlights the importance of motor function in the preclinical phase of both dementia and parkinsonism and may aid in selecting individuals for refined screening and neuroprotective trials.

Keywords: Dementia; Parkinsonism; Preclinical study; Prediction.