Split hand and motor axonal hyperexcitability in spinal and bulbar muscular atrophy.
J Neurol Neurosurg Psychiatry
; 91(11): 1189-1194, 2020 11.
Article
em En
| MEDLINE
| ID: mdl-32934003
ABSTRACT
OBJECTIVE:
The 'split hand' sign refers to preferential wasting of the thenar and first dorsal interosseous muscles with relatively sparing of the hypothenar muscles in amyotrophic lateral sclerosis (ALS) and both cortical and spinal/peripheral excitotoxic mechanisms have been proposed. We aimed to study split hand and axonal excitability in spinal and bulbar muscular atrophy (SBMA) in which cortical motor neurons are intact.METHODS:
In 35 patients with genetically confirmed SBMA, 55 with ALS, 158 with other neuromuscular diseases and 90 normal controls; split hand was strictly determined by amplitudes of compound muscle action potentials. Nerve excitability testing of median motor axons was performed in 35 SBMA and 55 patients with ALS and 45 normal controls.RESULTS:
Split hand was as frequently found for patients with SBMA (57%) and ALS (62%), compared with disease (20%) and normal (0%) controls. Excitability testing showed that in both SBMA and ALS, strength-duration time constant was longer, and threshold changes in depolarising threshold electrotonus and superexcitability in the recovery cycle were greater than in normal controls (p<0.01).CONCLUSIONS:
Split hand is not specific to ALS and can be caused by the peripheral mechanism alone in SBMA, whereas the effect of upper motor neuron lesion cannot be excluded in ALS. Our results also suggest that SBMA and ALS share common axonal excitability changes; increased nodal persistent sodium and reduced potassium currents that may accelerate motor neuronal death and differently affect axons-innervating different muscles. Ion channel modulators could be a therapeutic option for both SBMA and ALS.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Potenciais de Ação
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Atrofia Muscular
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Atrofia Bulboespinal Ligada ao X
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Mãos
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Esclerose Lateral Amiotrófica
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Nervo Mediano
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
J Neurol Neurosurg Psychiatry
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Japão