Split hand syndrome in amyotrophic lateral sclerosis: different excitability changes in the thenar and hypothenar motor axons

Shibuya, Kazumoto; Misawa, Sonoko; Nasu, Saiko; Sekiguchi, Yukari; Mitsuma, Satsuki; Beppu, Minako; Ohmori, Satoshi; Iwai, Yuta; Ito, Shingo; Kanai, Kazuaki; Sato, Yasunori; Kuwabara, Satoshi

doi:10.1136/jnnp-2012-304109

Cited by 79 publications

(69 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nerve conduction velocity showed compound motor action potential recorded in APB (median nerve at wrist) to be 4.3 mV and ADM (ulnar nerve at wrist) to be 5.0 mV with ratio <1, suggestive of split hand phenomenon of ALS, normal sensory nerve action potential and normal F-wave latency in bilateral median, ulnar and femoral nerves, ruling out the possibility of multifocal motor neuropathy with conduction block. Although hyperexcitability of APB was thought to be a cause for preferential wasting, this was not observed in our patient 1. Electromyography showed evidence of active denervation with fibrillation and fasciculation potentials in bilateral APB, FDI, deltoid and quadriceps muscles.…”

Section: Descriptioncontrasting

confidence: 60%

Amyotrophic lateral sclerosis presenting as typical split hand syndrome

Nalabothu

Monigari²,

Vellalacheruvu

et al. 2014

BMJ Case Reports

View full text Add to dashboard Cite

DESCRIPTIONA 38-year-old man presented to a hospital with weakness of both hands (right>left) with associated generalised weakness for the past 2 years. The patient initially noticed weakness and thinning of his right hand followed by the left for 2 years, then he noticed a thinning of the arms, right more so that left, and his right thigh for the past 6 months. General examination showed flattening over the right shoulder and wasting of the thenar eminence on both hands with normal hypothenar muscles (figures 1 and 2). Nervous system examination showed tongue fasciculations and significant asymmetrical wasting of abductor pollicis brevis (APB), and first dorsal interossei (FDI) with sparing of abductor digiti minimi (ADM) was noted (figures 1 and 2), but strength was normal in all four limbs with the exception of bilateral weak pincer grip. The patient had wasting of both arms (circumference 10 cm above the olecranon process was 18 and 21 cm for the right and left arms, respectively) and right thigh (circumference 10 cm above tibial tuberosity was 35 cm with left side being 40 cm). The patient had exaggerated reflexes in all four limbs with flexor plantar response and fasciculations most noticeably in deltoid, pectoral and quadriceps muscles suggesting definitive diagnosis of amyotrophic lateral sclerosis (ALS) by EL Escorial criteria. Other cranial nerves, motor, sensory and

show abstract

Section: Descriptioncontrasting

confidence: 60%

Amyotrophic lateral sclerosis presenting as typical split hand syndrome

Nalabothu

Monigari²,

Vellalacheruvu

et al. 2014

BMJ Case Reports

View full text Add to dashboard Cite

show abstract

“…Also, cortical hyperexcitability, a consistent feature of ALS (Vucic et al , 2006), has been shown to be associated with the split hand in ALS (Bae et al , 2014). Peripherally, motor axons innervating abductor pollicis brevis (APB) have physiologically higher excitability than those supplying abductor digiti minimi (ADM), and peripheral hyperexcitabilty in ALS in more pronounced in APB than ADM axons (Shibuya et al , 2013).…”

Section: Als Hand Function and Mirror Neuronsmentioning

confidence: 99%

Does dysfunction of the mirror neuron system contribute to symptoms in amyotrophic lateral sclerosis?

Eisen

Lemon

Kiernan

et al. 2015

Clinical Neurophysiology

View full text Add to dashboard Cite

Eisen et al, Mirror Neurons in ALS 2 Declaration of interest:The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Eisen et al, Mirror Neurons in ALS 3 Abbreviations:ALS: Amyotrophic lateral sclerosis; ADM: adductor digiti minimi; APB: abductor pollicic brevis; bvFTD: Behavioral variant of frontotemporal dementia; FTD: Frontotemporal dementia; fMRI: functional MRI; MNS: Mirror neuron system; M1: Primary motor cortex; PTNs: Pyramidal tract neurons; vMPFC: Ventral medial prefrontal cortex. Eisen et al, Mirror Neurons in ALS 4 AbstractThere is growing evidence that mirror neurons, initially discovered over two decades ago in the monkey, are present in the human brain. In the monkey, mirror neurons characteristically fire not only when it is performing an action, such as grasping an object, but also when observing a similar action performed by another agent (human or monkey). In this review we discuss the origin, cortical distribution and possible functions of mirror neurons as a background to exploring their potential relevance in amyotrophic lateral sclerosis (ALS). We have recently proposed that ALS (and the related condition of frontotemporal dementia) may be viewed as a failure of interlinked functional complexes having their origins in key evolutionary adaptations. The mirror neuron system is considered by many to be the basis of primates' social cognition, with a clear evolutionary advantage. Impaired empathy and motor control has been related to a defective mirror neuron system. In ALS, the mirror neuron system might be implicated in empathy, the split-hand syndrome, gait, speech, and related languagegesture impairments.Eisen et al, Mirror Neurons in ALS 5

show abstract

“…Studies in healthy controls have reported more prominent persistent Na + conductances and less K + currents in the APB and FDI motor axons [5], thereby suggesting that motor axons innervating the APB/FDI were hyperexcitable and prone to degeneration. Underscoring this notion were findings of more prominent hyperexcitability of APB axons in a Japanese ALS cohort [17]. In contrast, a more recent study established that axonal dysfunction was evident across the range of intrinsic hand muscles and was not consistent with a split-hand distribution [18].…”

Section: Introductionmentioning

confidence: 99%

Cortical Dysfunction Underlies the Development of the Split-Hand in Amyotrophic Lateral Sclerosis

2014

View full text Add to dashboard Cite

The split-hand phenomenon, a specific feature of amyotrophic lateral sclerosis (ALS), refers to preferential wasting of abductor pollicis brevis (APB) and first dorsal interosseous (FDI) with relative preservation of abductor digiti minimi (ADM). The pathophysiological mechanisms underlying the split-hand phenomenon remain elusive and resolution of this issue would provide unique insights into ALS pathophysiology. Consequently, the present study dissected out the relative contribution of cortical and peripheral processes in development of the split-hand phenomenon in ALS. Cortical and axonal excitability studies were undertaken on 26 ALS patients, with motor responses recorded over the APB, FDI and ADM muscles. Results were compared to 21 controls. Short interval intracortical inhibition (SICI), a biomarker of cortical excitability, was significantly reduced across the range of intrinsic hand muscles (APBSICI ALS 0.3±2.0%, APBSICI controls 16.0±1.9%, P<0.0001; FDISICI ALS 2.7±1.7%, FDI SICI controls 14.8±1.9%, P<0.0001; ADMSICI ALS 2.6±1.5%, ADM SICI controls 9.7±2.2%, P<0.001), although the reduction was most prominent when recorded over APB/FDI. Changes in SICI were accompanied by a significant increase in motor evoked potential amplitude and reduction of cortical silent period duration, all indicative of cortical hyperexcitability, and these were most prominent from the APB/FDI. At a peripheral level, a significant increase in strength-duration time constant and reduction in depolarising threshold electrotonus were evident in ALS, although these changes did not follow a split-hand distribution. Cortical dysfunction contributed to development of the split-hand in ALS, thereby implying an importance of cortical hyperexcitability in ALS pathogenesis.

show abstract

Split hand syndrome in amyotrophic lateral sclerosis: different excitability changes in the thenar and hypothenar motor axons

Cited by 79 publications

References 22 publications

Amyotrophic lateral sclerosis presenting as typical split hand syndrome

Amyotrophic lateral sclerosis presenting as typical split hand syndrome

Does dysfunction of the mirror neuron system contribute to symptoms in amyotrophic lateral sclerosis?

Cortical Dysfunction Underlies the Development of the Split-Hand in Amyotrophic Lateral Sclerosis

Contact Info

Product

Resources

About