Motor Imagery Promising in Motor Rehabilitation in Parkinsons

The report covered in this summary was published on medRxiv.org as a preprint and has not yet been peer reviewed.

Key Takeaway

• Functional connectivity-based neurofeedback regulation was unsuccessful in improving motor performance in a cohort with mild Parkinson’s disease. However, kinesthetic motor imagery practice by itself or in combination with other imagery techniques is a promising intervention in motor rehabilitation in Parkinson’s disease.

Why This Matters

• Parkinson’s causes difficulty with maintaining the speed, size, and vigor of movements, especially when they are internally generated.

• The authors previously proposed that the insula is important in motivating intentional movement via its connections with the dorsomedial frontal cortex (dmFC). They demonstrated that subjects with Parkinson’s can increase the right insula-dmFC functional connectivity using functional MRI-based neurofeedback combined with kinesthetic motor imagery.

• The current study is a randomized clinical trial testing whether neurofeedback-guided kinesthetic motor imagery training can improve motor performance and increase task-based and resting-state right insula-dmFC functional connectivity in subjects with Parkinson’s.

Study Design

• In a randomized trial, the authors assigned nondemented subjects with mild Parkinson’s (Hoehn & Yahr stage ≤ 3) to the experimental kinesthetic motor imagery with neurofeedback (NF) and active control visual imagery (VI) groups.

• Only the motor imagery-neurofeedback (MI-NF) group received NF-guided MI training (10-12 runs).

• The NF signal was based on the right insula-dmFC functional connectivity strength.

• All subjects also practiced their respective imagery tasks at home daily for four weeks.

• Post-training changes in 1) task-based and resting-state right insula-dmFC functional connectivity were the imaging outcomes, and 2) MDS-Unified Parkinson’s Disease Rating Scale motor exam and motor function scores were the clinical outcomes.

Key Results

• The MI-NF group did not show significant NF regulation and was not significantly different from the VI group in any of the imaging or clinical outcome measures.

• The MI-NF group reported subjective improvement in kinesthetic body awareness.

• Both groups showed specific training effects in whole-brain functional connectivity with distinct neural circuits supporting kinesthetic motor and visual imagery (exploratory outcome).

Limitations

• Involuntary muscle contraction as a result of motor imagery can potentially confound MRI findings.

• The authors did not monitor muscle activity in the scanner using surface EMG electrodes.

• Although the authors did not observe overt movements while subjects were in the scanner and head motion levels in the scanner across both groups were equivalent, they could not rule out covert muscle contractions.

• The authors also did not track eye movements during imagery blocks, and therefore could not assess whether subjects in both groups were matched in the amount of eye movement.

• The training and assessment of outcome measures were limited to a 4-week period with no follow-up. However, continued symptomatic benefits for weeks after NF have been demonstrated in clinical populations.

Study Disclosures

• The authors declare no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

This is a summary of a preprint research study, “Neurofeedback-guided kinesthetic motor imagery training in Parkinson’s disease: Randomized trial,” by Sule Tinaz, MD, PhD, from Yale University School of Medicine, New Haven, Connecticut, provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on medRxiv.org.

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