Progressive Worsening of Gait and Motor Abnormalities in Older Adults With Dravet Syndrome

BACKGROUND AND OBJECTIVES: Relative to the pediatric population, there is limited information about Dravet syndrome (DS) in adults. In addition to some of the gait abnormalities reported in children with DS (such as crouch gait and ataxia), adults with this condition have other gait and motor disturbances. Our primary objective was to examine gait and motor manifestations in adults with DS. METHODS: This study includes a prospective arm where 6 patients (mean age, 32 years) were examined through a modified version of the Unified Parkinson's Disease Rating Scale (mUPDRS) in 2014 and again in 2019. mUPDRS scores were assigned to gait, resting tremors, facial expression, arising from a chair, posture, and body bradykinesia. The cross-sectional arm includes mUPDRS testing in patients who were not evaluated in 2014 and an instrumental gait analysis (IGA). These cross-sectional tests were done in the 2019–2020 period. The IGA was performed using ProtoKinetics software with a gait mat built with sensors and 2 cameras capturing the sagittal and coronal planes. The IGA was performed in a group of 17 patients with DS (mean age, 31 years); the control group consisted of 81 healthy individuals, whose mean age was 62 years. Regression analyses were performed for the IGA and mUPDRS data. RESULTS: Five out of 6 participants evaluated prospectively over 5 years experienced worsening of their parkinsonian manifestations, including gait. Two patients (47 and 51 years of age) who were initially ambulatory could no longer walk 5 years later. The cross-sectional analysis of mUPDRS in a larger group of adults showed that worse scores for arising from a chair (p = 0.04), body bradykinesia (p = 0.01), and gait (p = 0.0003) were positively associated with age. The IGA cross-sectional arm revealed that all 17 adults with DS had abnormal gait measures in all domains tested. This group of patients performed worse than the healthy and older control group. DISCUSSION: Although seizures may decrease in older adults with DS, this prospective and cross-sectional study showed that their motor symptoms and gait become progressively worse as they age.