Utility of split hand index with different motor unit number estimation techniques in ALS

Nathan Pavey; Andrew Hannaford; Mana Higashihara; Mehdi van den Bos; Matthew C Kiernan; Parvathi Menon; Steve Vucic

doi:10.1016/j.clinph.2023.09.018

Utility of split hand index with different motor unit number estimation techniques in ALS

Clin Neurophysiol. 2023 Dec:156:175-182. doi: 10.1016/j.clinph.2023.09.018. Epub 2023 Oct 26.

Authors

Nathan Pavey¹, Andrew Hannaford¹, Mana Higashihara², Mehdi van den Bos¹, Matthew C Kiernan³, Parvathi Menon¹, Steve Vucic⁴

Affiliations

¹ Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW Australia.
² Department of Neurology, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan.
³ Brain and Mind Centre, The University of Sydney; and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia.
⁴ Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW Australia. Electronic address: [email protected].

PMID: 37967511
DOI: 10.1016/j.clinph.2023.09.018

Abstract

Objective: Utility of the split hand index (SI) in amyotrophic lateral sclerosis (ALS) has been reported when using the compound muscle action potential (CMAP) amplitude method (SI_{CMAP amp}). A motor unit number index (MUNIX) based SI method (SI_MUNIX) was purported to exhibit higher sensitivity. The present study assessed the clinical utility of SI, derived by CMAP amplitude, MUNIX and MScan-MUNE (SI_{MScanFit-MUNE}) methods, in ALS.

Methods: Sixty-two consecutive patients with neuromuscular symptoms (36 ALS and 26 ALS-mimics) were prospectively recruited. The SI was derived by dividing the product of the CMAP amplitude, MUNIX and MScan-MUNE values recorded over first dorsal interosseous and abductor pollicis brevis by values recorded over abductor digit minimi.

Results: SI_{CMAP amp}, SI_MUNIX and SI_{MScanFit-MUNE} were significantly reduced in ALS, with SI_{CMAP amp} (area under curve (AUC) = 0.801) and SI_{MScanFit-MUNE} (AUC = 0.805) exhibiting greater diagnostic utility than SI_MUNIX (AUC = 0.713). SI_{CMAP amp} and SI_{MScanFit-MUNE} exhibited significant correlations with clinical measures of functional disability and weakness of intrinsic hand muscles.

Conclusions: SI differentiated ALS from mimic disorders, with SI_{CMAP amp} and SI_{MScanFit-MUNE} exhibiting greater utility.

Significance: The split hand index represents could serve as a potential diagnostic biomarker in ALS.

Keywords: ALS subtypes; Region of clinical disease onset; Split-hand index.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Action Potentials / physiology
Amyotrophic Lateral Sclerosis* / diagnosis
Area Under Curve
Electromyography / methods
Hand
Humans
Muscle, Skeletal