The electrodiagnostic features of acute childhood Guillain-Barré syndrome (GBS) have not been distinguished from those in the adult. We report nerve conduction and electromyographic data from 23 children. Sixty-one percent (14 of 23) fulfilled strict electrodiagnostic criteria for a demyelinating neuropathy, and the remainder demonstrated demyelination in at least one nerve. Reduced compound muscle action potential (CMAP) amplitude was the most common finding overall. Children less than 10 years old demonstrated significantly greater slowing of motor CV than children greater than 10 years old. Electrodiagnostic criteria associated with poor outcome (low mean CMAP and fibrillation potentials) in previous studies, primarily of adult patients, occurred in 39% (9 of 23 children). All patients on whom follow-up data were obtained recovered without residual disability. We conclude that electrodiagnostic prognostic indicators identified in general series of GBS may not apply to children.

Eighty infants with nonarthrogrypotic floppy infant syndrome (FIS) were evaluated between 1979 and 1990. Electromyographic data were correlated with results of muscle and nerve biopsies in 41 of 80 who had concomitant biopsies (38) or other diagnostic analyses (3). A diagnosis was made of Werdnig-Hoffmann disease (WHD) in 15, a congenital infantile polyneuropathy (IPN) in 3, neuromuscular transmission defect (NMTD) in 2, myopathy in 12, and presumed "central" hypotonia in 9. A very positive correlation rate between nerve conduction studies with electromyography and biopsy results was found in 93% (14 of 15) with WHD and 100% in IPN (3 of 3). However, only 4 of 10 infants (40%) with biopsy-proven myopathy had an abnormal EMG. Only once did the results of electromyography and biopsy conflict.