Neurología : publicación oficial de la Sociedad Española de Neurología
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Fluctuating stiffness and paroxysmal spasms of the trunk and legs are the primary features of stiff-man syndrome and it's variants, progressive encephalomyelopathy with rigidity and myoclonus (PERM) and stiff-leg syndrome. The spasms characterized by hyperextension of the back and legs are both spontaneous as well as stimulus-sensitive. They can be excruciatingly painful and are frequently accompanied by symptoms of autonomic dysregulation. ⋯ It consists of well-reproduced reflex EMG-activity commencing 50-80 ms after medial or tibial nerve stimulation and lasting several seconds thereafter. The activity is first myoclonic then spasmodic in nature, and commonly begins in the muscles most severely affected before spreading bidirectionally along the neuraxis. Spasmodic reflex myoclonus and the high incidence of antibodies against GAD are suggestive of an autoimmune disorder affecting GABAergic neurons in the spinal cord, but the precise locus of dysfunction remains to be elucidated.