2nd Workshop Neurogenetics in Germany, Munich, October 19-21, 1995
Unintended activity of homologous opposite muscles during unilateral voluntary movements may persist into adulthood. This abnormality, persistent mirror movements (PMM), occurs in various genetic conditions.
Twelve affected subjects were investigated for variables influencing the pattern of PMM (1 patient with Wildervanck's syndrome, 5 with Kallmann's, 6 autosomal dominant PMM).
Force transducers were held between thumb and index of both hands. One hand repetitively changed grip force in different 15 s trials according to instruction (combinations of "20%" and "50% of maximum force" and of "1/s" and "maximal speed"). The other hand was to be kept still.
During all trials, however, mirror activity (MA) of identical as voluntary frequency occurred. 60 controls showed inconstant MA. Although MA was present in all hands of PMM subjects, its amount differed by at least a factor of 2 between hands in 6 patients. Presence and direction of this asymmetry appeared unrelated to sex or age, to preferred or stronger hand, to force amplitude or frequency. Three subjects with dominant PMM showed greater MA on the left, whereas three subjects with Kallmann's syndrome showed greater MA on the right.
Thus, the phenotype of persistent mirror movements seems heterogeneous. lt might be related to the underlying genetic syndrome.
(Support: Wilhelm-Sander-Stiftung 91.031.1-2)
persistent mirror movements (PMM)