Split Hand—ALSに特徴的な神経徴候

Split Hand: characteristic neurological symptoms in ALS

Split handとは，母指球筋や第一背側骨間筋が萎縮するのに対し，小指球筋が比較的保たれる現象を指す。この所見は，筋萎縮性側索硬化症（ALS）に特異的に認められると考えられている。本論ではsplit handを含め，ALSに特徴的な筋力低下や筋萎縮の分布，神経徴候を概説し，これらの徴候の背景病態やALS診断における有用性を考察する。

Abstract

‘Split hand’ is dissociated hand muscle atrophy, characterized by preferential atrophies in the thenar and first dorsal interosseous muscles, with relative sparing of the hypothenar muscle. This symptom has been recognized as specific to amyotrophic lateral sclerosis (ALS), and distinct pathomechanisms are assumed to underlie this phenomenon. Recently, characteristic distributions of weakness and symptoms in ALS have been reported. Here, we describe characteristic symptoms of ALS, including split hand, split-hand plus sign, split elbow, split leg, relative preservation of finger flexion. Moreover, through these phenomena, potent mechanisms of motor neuron death in ALS are considered. Revealing the underlying pathophysiology of these symptoms may lead to the development of therapies for ALS.