The neurophysiology of the alternating leg muscle activation (ALMA) during sleep: study of one patient before and after treatment with pramipexole.

Abstract Background and purposes To report the neurophysiological features of a patient with alternating leg muscle activation (ALMA) during sleep, a quickly alternating pattern of anterior tibialis activation which might represent transient facilitation of a spinal central pattern generator for locomotion, perhaps due to the serotonergic effects of antidepressant medication. Patient and methods A 33-year-old male patient with ALMA. The patient underwent a complete and detailed study of his neurophysiological parameters during sleep, before and after treatment with pramipexole. Results The treatment with pramipexole was followed by a significant reduction in the rate of occurrence of ALMA, in reported insomnia, and in daytime sleepiness. The ALMA generally were preceded by cyclic alternating pattern A phases and increased heart rate in most instances. Visual scoring and spectral analyses suggested that after pramipexole more intense arousal was required to trigger ALMA. Conclusion The evident beneficial effect induced by the treatment with pramipexole indicates that the spinal networks involved in the generation of ALMA might also be under the inhibitory control of dopaminergic networks. We suggest that ALMA can be seen even in the absence of other factors such as antidepressant therapy, sleep apnea or periodic leg movements during sleep, and might be considered as an additional phenomenon influenced by sleep instability. Our patient seems to indicate also that treatment with dopamine agonists can be useful in such patients because the treatment can be followed by a good clinical response.