Session Information
Date: Tuesday, June 6, 2017
Session Title: Rare Genetic and Metabolic Diseases
Session Time: 1:45pm-3:15pm
Location: Exhibit Hall C
Objective: To compare FXTAS, PD, ET and controls using quantitative measures of gait, balance, and tremor.
Background: Fragile X-associated tremor/ataxia syndrome (FXTAS), a neurodegenerative disease that affects carriers of a 55-200 CGG repeat expansion in the fragile X mental retardation 1 gene, may be misdiagnosed as PD or ET due to overlapping motor symptoms. It is critical to characterize distinct phenotypes in FXTAS compared to PD and ET to improve diagnostic accuracy. Environmentally challenging and dual-task (DT) paradigms can reveal subtle gait and balance impairments, and tremorography correlates with clinical tremor rating scale scores.
Methods: Subjects with FXTAS (n = 10; mean age 69.70 ± 6.81 years), PD (n = 15; mean age 70.87 ± 7.97 years) and ET (n = 9; mean age 69.56 ± 7.35 years) and controls (n = 12; mean age 64.42 ± 7.12 years) underwent gait and balance testing with an inertial sensor system (APDM; Oregon). Instrumented Timed Up and Go (i-TUG) and 2-minute walk (i-WALK) tests were used to test gait, and the i-SWAY to test balance. DT conditions included a verbal fluency task. Subjects also underwent tremorography using the ETSenseTM system (Kinesia HomeViewTM; Great Lakes NeuroTechnologies Inc.).
Results: On the i-TUG, FXTAS subjects had increased sit-to-stand peak velocity compared to PD subjects (p=0.04). On self-selected speed and DT i-WALKs, they had increased stride length (p=0.03 and 0.04, respectively), and during self-selected and fast i-WALKS they had reduced cadence (p=0.03 and 0.04, respectively) compared to PD subjects. On the i-SWAY, both FXTAS and ET subjects had increased jerk (m2/s5; smoothness of path sway) compared to PD subjects during the foam, feet apart, and eyes closed condition (p=0.01 and 0.04, respectively). On tremorography, FXTAS subjects showed reduced rapid alternating movement amplitude compared to PD subjects (p = 0.0045), and PD subjects showed reduced rapid alternating movement amplitude and speed compared to ET subjects (p=0.0002 and 0.0115, respectively).
Conclusions: This pilot data demonstrates that FXTAS, PD, and ET subjects exhibit distinct deficits in gait, balance and tremor under normal, environmentally challenging and DT conditions. This suggests that these quantitative measures may be sensitive to distinguish FXTAS from PD and ET.
To cite this abstract in AMA style:
E. Robertson, D. Hall, A. McAsey, M. Swanson, A. Bery, C. Huml, E. Berry-Kravis, J. O'Keefe. FXTAS, PD, and ET subjects demonstrate distinct gait, balance and tremor deficits under normal, environmentally challenging, and dual-task conditions [abstract]. Mov Disord. 2017; 32 (suppl 2). https://www.mdsabstracts.org/abstract/fxtas-pd-and-et-subjects-demonstrate-distinct-gait-balance-and-tremor-deficits-under-normal-environmentally-challenging-and-dual-task-conditions/. Accessed June 14, 2025.« Back to 2017 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/fxtas-pd-and-et-subjects-demonstrate-distinct-gait-balance-and-tremor-deficits-under-normal-environmentally-challenging-and-dual-task-conditions/