SOURCE: Annual International Conference Of The IEEE Engineering In Medicine And Biology Society. 2022:4383-4386, 2022 Jul.
AUTHORS: Uehara MA; Francisco CO; Lithgow B; Koski L; Moussavi Z
ABSTRACT: Conflicting results have emerged from studies examining the potential of resting motor threshold (RMT) as a neurophysiological marker for Alzheimer’s disease (AD) diagnosis and progression. In this study, we estimated the strength of the association between RMT measurements and severity of cognitive impairment in a relatively large sample (N=128) of clinical trial participants with mild (Clinical Dementia Rating – CDR=1) to moderate (CDR=2) AD. RMT for each participant was determined by applying single-pulse transcranial magnetic stimulation repeated at
varying intensities over left and right sides of the primary motor cortex. RMT is the minimum intensity that evoked a visible contralateral involuntary finger twitch and RMT asymmetry is the absolute difference between the left and right RMT measurements. Cognitive impairment was
measured with the Montreal Cognitive Assessment (MoCA) and the Alzheimer Disease Assessment Scale – Cognitive (ADAS-Cog) scores. Although the left and right RMT was lower in CDR 2 than in CDR 1 participants, neither RMT nor RMT asymmetry correlated significantly with cognitive test scores. In conclusion, our study in a large sample size does not support the idea that RMT is a sensitive marker of cognitive decline/severity in AD. Clinical Relevance- This study provides evidence that RMT may not be useful for AD progression monitoring.
