Cognitive function impacts gait, functional mobility and falls in fragile X-associated tremor/ataxia syndrome

• Published in: Gait & posture Vol. 66; pp. 288 - 293
• Main Authors: O’Keefe, Joan A., Robertson, Erin E., Ouyang, Bichun, Carns, Danielle, McAsey, Andrew, Liu, Yuanqing, Swanson, Maija, Bernard, Bryan, Berry-Kravis, Elizabeth, Hall, Deborah A.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.10.2018
• Subjects: Accidental Falls - statistics & numerical data; Aged; Ataxia - complications; Ataxia - physiopathology; Cognition - physiology; Cognition Disorders - complications; Cognitive function; Executive Function - physiology; Fall risk; Female; Fragile X Syndrome - complications; Fragile X Syndrome - physiopathology; Fragile X-associated tremor/ataxia syndrome (FXTAS); Gait Analysis - methods; Gait and functional mobility; Gait Disorders, Neurologic - etiology; Humans; Instrumented Timed Up and Go (i-TUG); Male; Middle Aged; Neuropsychological Tests; Range of Motion, Articular; Retrospective Studies; Tremor - complications; Tremor - physiopathology; Walking Speed - physiology; Gait and functional mobility; Fragile X-associated tremor/ataxia syndrome (FXTAS); Fall risk; Instrumented Timed Up and Go (i-TUG); Cognitive function
• ISSN: 0966-6362; 1879-2219; 1879-2219
• DOI: 10.1016/j.gaitpost.2018.09.005

•Cognitive deficits negatively impact gait and functional mobility in FXTAS.•Slower processing speed associated with worse gait speed in subjects with FXTAS.•Lower response inhibition associated with slower turn-to-sit performance in FXTAS.•Lower working memory and processing speed correlate with falls in FXTAS.•This information will inform the design of cognitive/motor interventions in FXTAS. Executive function and information processing speed deficits occur in fragile X premutation carriers (PMC) with and without fragile X-associated tremor/ataxia syndrome (FXTAS). Gait is negatively impacted by cognitive deficits in many patient populations resulting in increased morbidity and falls but these relationships have not been studied in FXTAS. We sought to investigate the associations between executive function and information processing speed and gait, turning and falls in PMC with and without FXTAS compared to healthy controls. Global cognition and the cognitive domains of information processing speed, attention, response inhibition, working memory and verbal fluency were tested with a neuropsychological test battery in 18 PMC with FXTAS, 15 PMC without FXTAS, and 27 controls. An inertial sensor based instrumented Timed Up and Go was employed to test gait, turns and functional mobility. Lower information processing speed was significantly associated with shorter stride length, reflecting slower gait speed, in PMC with FXTAS (p = 0.0006) but not PMC without FXTAS or controls. Lower response inhibition was also significantly associated with slower turn-to-sit times in PMC with FXTAS (p = 0.034) but not in those without FXTAS or controls. Lower information processing speed (p = 0.012) and working memory (p = 0.004), were significantly correlated with a greater number of self-reported falls in the past year in FXTAS participants. This is the first study demonstrating that worse executive function and slower information processing speed is associated with reduced gait speed and functional mobility, as well as with a higher retrospective fall history in participants with FXTAS. This information may be important in the design of cognitive and motor interventions for this neurodegenerative disorder.