Advanced EMG techniques in diagnostics of spinal muscular atrophies and motor neuron disease--magnetic stimulation, single fiber EMG and macro EMG.
Motor neuron disease (MND) and spinal muscular atrophies (SMA) are difficult to diagnose with classical EMG methods because significant findings appear relatively late and both groups of diseases show neurogenic type of record differing only in a relatively greater amount of fasciculations and higher amplitude of motor unit potential (MUP) in MND compared with SMA. We examined 12 patients with MND-amyotrophic lateral sclerosis and 7 patients with SMA type III and IV according to Swash with advanced EMG techniques-magnetic stimulation, single fiber and macro EMG. With transcranial magnetic stimulation, a significant prolongation of cortical latency was found in MND (P < 0.0001 right hand and P < 0.0005 left hand) against SMA, where it was almost normal. With single fiber EMG, mean jitter was less markedly increased in MND (P < 0.05 against SMA) and fiber density was lower in MND (P < 0.005). With macro EMG, no significant difference was found in either macro amplitude or area. Macro fiber density was also lower in MND (P < 0.005). Advanced EMG techniques proved to differentiate clearly the III. (Kugelberg-Welander) and IV. (adult) type of SMA from MND-amyotrophic lateral sclerosis.
Bartousek
J
J
EMG Laboratory, Clinic of Neurology, Medical Faculty, Palacký University, Olomouc, Czech Republic.
Hlustík
P
P
Grenarová
O
O
Beranová
M
M
D000328:Adult; D000368:Aged; D004576:Electromyography / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000175:diagnosis*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D009134:Muscular Atrophy, Spinal / Q000175:diagnosis*