Case A 40-year-old man was admitted to our hospital complaining of weakness and atrophy in his both hands.He experienced weakness abruptly in bilateral hands, resulting in decreased grip strength and clumsiness when he was doing exercise 20 years ago.Then the weakness persisted and did not recover to normal after resting.2 mounths later he noticed muscle atrophy of bilateral hands.His symptoms were gradually stable in the following 20 years.But recently he felt the handsweakness worsened, and had some difficulty working in computer.