The importance of parkinsonian signs for gait and balance in patients with Alzheimer's disease of mild degree

Parkinsonian signs are common in patients with Alzheimer's disease (AD) of mild degree and predict functional decline, but their relationship with gait speed and balance is unclear. The aims of this study were to describe characteristics of patients with parkinsonian signs among 98 patients with AD of mild degree (with no comorbid Parkinson's disease), and to examine associations between parkinsonian signs with gait speed and balance. A cross sectional study at a memory clinic was conducted. Presence of each parkinsonian sign (bradykinesia, rigidity and tremor) was derived from the UPDRS, regular gait speed was recorded over 10 m and balance were assessed using the Mini-Balance Evaluation Systems Test (Mini-BESTest). Bradykinesia was present in 30.6% of the sample, rigidity in 13.3% and tremor only in one patient. Patients with bradykinesia were older, had worse cognitive impairment and worse gait and balance performance than those without bradykinesia. More men than women had rigidity. Bradykinesia was significantly associated with mini-BESTest after adjusting for demographic factors (p < 0.001, explaining 13.3% of the variance), but was not significantly associated with gait speed. Rigidity was not associated with either gait speed or balance. We conclude that assessment of bradykinesia should be included in examination of balance control in patients with AD of mild degree.