Patterns of clinical and electrodiagnostic abnormalities in early amyotrophic lateral sclerosis

INTRODUCTION: The distribution of clinical and neurophysiological abnormalities in patients with early amyotrophic lateral sclerosis (ALS) was investigated in an attempt to delineate patterns of disease spread. METHODS: Clinical and electrodiagnostic data were collected from 150 ALS patients and analyzed based on the clinical region of onset. RESULTS: Asymmetry of clinical and neurophysiological abnormalities was more marked in upper limb-onset than lower limb-onset disease. Significant rostral-caudal gradients of clinical weakness were identified in bulbar- and lower limb-onset disease. Neurophysiological evidence of the ALS "split-hand" pattern was evident irrespective of the region of disease onset. Limbs with and without evidence of clinical weakness demonstrated similar rates of abnormality on electromyography. CONCLUSIONS: These findings suggest a pattern of disease spread in ALS. This study may serve to guide ongoing development of disease quantitation biomarkers and the targeting of future neuroprotective strategies.