Neural Correlates of Motor Imagery of Gait in Amyotrophic Lateral Sclerosis
Malek Abidi, Giovanni de Marco, Fatma Grami, Nicolas Termoz, Annabelle Couillandre, Giorgia Querin, Peter Bede, Pierre‐François Pradat
Abstract
BACKGROUND: Gait impairment is poorly characterized in amyotrophic lateral sclerosis (ALS), despite increasing evidence of extrapyramidal and cerebellar dysfunction. Gait impairment adds to the considerable motor disability of ALS patients and requires targeted multidisciplinary interventions. PURPOSE: To assess gait imagery-specific networks and functional adaptation in ALS. STUDY TYPE: Prospective. POPULATION: Seventeen ALS patients with lower motor neuron predominant (LMNp) disability, 14 patients with upper motor neurons predominant (UMNp) disease, and 14 healthy controls were included. FIELD STRENGTH/SEQUENCES: 3T / gradient echo echo planar (GE-EPI). ASSESSMENT: Subjects performed a dual motor imagery task: normal and precision gait. The Movement Imagery Questionnaire - Revised Second Version (MIQ-rs) was used to appraise movement imagery in each participant. Study group-specific activation patterns were evaluated during motor imagery of gait. Additional generalized psychophysiological interaction analyses were carried out using the supplementary motor area, caudate, cerebellum, and superior parietal lobule as seed regions. STATISTICAL TESTS: Repeated-measures analysis of variance (ANOVA) was used to compare time imagery and MIQ-rs scores between groups. Size effects were also reported as partial eta squared (η2). One-way ANOVA was performed to explore differences in terms of connexions during motor imagery tasks. RESULTS: < 0.05), posterior parietal (pFDR < 0.05) caudate (pFDR < 0.05), and cerebellar (pFDR < 0.05) signal during imagined locomotion. Increased effective connectivity of the striato-cerebellar and parieto-cerebellar circuits was also demonstrated. Additional activation was detected in the insula and cingulate cortex. DATA CONCLUSION: Enhanced striato- and parieto-cerebellar networks in UMNp ALS patients are likely to represent a compensatory response to impaired postural control. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 5.