The Effect of Repetitive Transcranial Magnetic Stimulation of the Dorsolateral Prefrontal Cortex on the Amyotrophic Lateral Sclerosis Patients With Cognitive Impairment: A Double-Blinded, Randomized, and Sham Control Trial

Background

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. A large number of ALS patients have cognitive impairment. In this double-blinded, randomized, and sham-controlled study, we aimed to investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on ALS patients with cognitive impairment.

Methods

A total of 90 ALS patients with cognitive impairment were recruited from two cohorts; 80 participants were randomly assigned in a 1:1 ratio to receive 10 Hz rTMS or sham treatment on the bilateral dorsolateral prefrontal cortices (DLPFC) for 4 consecutive weeks. The patients were assessed by ECAS and ALSFRS-R scales. The Zarit care burden scale was administered to caregivers of ALS patients. The primary outcome measured was the rate of decline in the total ECAS score between pretreatment, 6 months post-treatment, and 12 months post-treatment. Secondary outcomes included the group difference in the slope of the Zarit score, ALSFRS-R total score, and the neurofilament light chain plasma levels.

Results

The ECAS total score in the intention-to-treat population significantly changed from 79.74 ± 6.39 to 81.98 ± 6.51 and 79.22 ± 6.50 with rTMS intervention at the 6-month and 12-month follow-ups, respectively (p = 0.031, p = 0.042). The Zarit score also significantly decreased from 57.65 ± 3.42 to 52.24 ± 3.34 and 56.42 ± 3.41 at the 3-month and 6-month post-treatment time points, respectively (p = 0.003, p = 0.014). No significant differences were observed between the groups for other secondary endpoints. However, there was a trend of decreasing NF-L level rates in the treatment group over the first 6 months' follow-up.

Conclusions

rTMS could yield short-term positive effects on the ALS patients subgroup with cognitive impairment and alleviate caregivers' burden. No improvement was observed in the severity of ALS and ALS plasma biomarkers.