Electromyography (EMG) identifies abnormalities in the neuronal hyperexcitability syndrome (NHS) with high frequencies of false positive results. We examined 25 subjects with autonomic, psychic and neuromuscular symptoms of NHS. They underwent the ischaemia-hyperpnea test using stringent time criteria to study their symptoms as well as their electrolytical balance. The Kaplan-Meier analysis showed a significantly different incidence of repetitive discharges in the two groups in the post-ischaemic period (p < 0.004) and during hyperpnea (p < 0.001). The ischaemia-hyperpnea EMG test, when evaluated in relation to the the duration of activation procedure, was able to differentiate NHS patients from controls only within 4-6 minutes of ischaemia or hyperpnea. When restricted to this period, EMG observation with the triggering of Ischaemia-hyperpnea identified NHS with a high degree of sensitivity and specificity.