Autonomic functions were studied in 10 respiratory-support patients wi
th motor neuron disease (MND) at its most advanced stage by means of h
emodynamic function tests, The mean duration of disease was 83.4 month
s (SD 28.0, range 50-140 months), All the patients in this study had l
ost their ability to breathe spontaneously and were ventilated by resp
irator. Hemodynamic function tests were performed in 8 out of 10 patie
nts, These patients showed exaggerated sympathetic vasomotor reflexes,
increased reflex hypertension and tachycardia in response to the cold
presser test and increased response to administration of adrenaline,
However, the responses to both the Aschner eyeball pressure test and i
njection of atropine were normal, indicating normal parasympathetic ne
rvous system function, Plasma and urine levels of norepinephrine, epin
ephrine and their metabolites were almost normal in all 10 patients, a
s were serum dopamine-beta-hydroxylase levels, In patients with the mo
st advanced stage of MND, hyperfunction of the adrenergic sympathetic
nervous system was observed, and this was considered to be a symptom c
haracteristic of MND.