Spatiotemporal gait parameters and tremor distribution in essential tremor.

BACKGROUND: Essential Tremor is characterized by an action tremor of the upper extremities, which may or may not be accompanied by a head, voice, leg or trunk tremor. Problems with gait and balance have also been identified in persons with Essential Tremor. Therefore, understanding gait performance is an important area of focus for clinicians and researchers. RESEARCH QUESTION: We sought to 1) conduct a factor analysis on a broad spectrum of spatiotemporal gait parameters 2) build upon the normative database of gait measures in persons with Essential Tremor 3) understand the influence of age on gait speed in persons with Essential Tremor and 4) identify the relationships between gait performance and clinical measures of disease severity. METHODS: Gait data and Tremor Rating Scale scores were retrospectively collected from one hundred and forty-two ambulatory participants with a diagnosis of Essential Tremor. A factor analysis was used to characterize spatiotemporal gait parameters and regression models were applied to associate tremor scores to gait performance factors. RESULTS: Three domains of gait performance factors were identified in persons with Essential Tremor. Specifically, we observed a pace, rhythm, and stability factor. In sum, these factors accounted for 91.9% of the variance in gait performance. Only the pace and stability factors were associated with disease severity, suggesting these factors are most sensitive to disease severity compared to the rhythm factor. Our linear regression analysis revealed a significant influence of age on gait speed. Gait speed decreased with age significantly by 0.64 cm/s/year. SIGNIFICANCE: Reference values for 12 gait parameters will be highly useful for assessing gait performance in individuals with Essential Tremor. Our observations suggest that a clinical assessment of gait and balance would be an important measure to consider in routine clinical practice when treating persons with Essential Tremor.