Abstract
F waves were recorded from the thenar and hypothenar muscles by the stimulation of the median and ulnar nerves at the elbow in 11 patients with Werdnig-Hoffmann disease (7 with functional motor level 1 (L1), 4 with the level 0 (L0)) and 25 normal subjects. F waves were analysed with regard to the frequency of appearance and the amplitude. F wave conduction velocity (FCV) from the cervical cord to the elbow was also measured. The following results were obtained; In Werdnig-Hoffmann disease the frequency of F wave appearance, and the amplitude of M and F waves were reduced as compared with normal subjects. With deteriorating the functional motor level, however, the amplitude of M and F waves significantly decreased in L0 than in L1. Knowing the above characteristics of the F wave, F wave analysis is recommended as a complimentary testing procedure to assess the functional motor level of Werdnig-Hoffmann disease.
