Disinhibition of somatosensory and motor cortex in mitochondriopathy without myoclonus.
OBJECTIVE
To test electrophysiologically, if patients with mitochondriopathy but without evidence of myocloni have subclinical signs of disinhibition in motor and somatosensory cortices.


METHODS
Two patients were studied and compared with age-matched control groups.


RESULTS
In both patients, giant somatosensory evoked potentials after median nerve stimulation and a reduced intracortical inhibition tested by transcranial magnetic stimulation in a paired pulse paradigm indicated a dysfunction of inhibitory circuits in the motor as well as the somatosensory cortex. In addition, the somatosensory evoked 600 Hz activity recorded by magnetoencephalography was abolished.


CONCLUSIONS
Patients with mitochondriopathy may suffer from a subclinical disturbance of inhibition in the sensorimotor cortex. The loss of 600 Hz activity indicates that these high-frequency oscillations could reflect the activity of inhibitory neurons in the somatosensory cortex.
Liepert
J
J
Department of Neurology, Friedrich Schiller University of Jena, Jena, Germany. liepert@uke.uni-hamburg.de
Haueisen
J
J
Hegemann
S
S
Weiller
C
C
D000328:Adult; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008280:Magnetics; D015225:Magnetoencephalography; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D017240:Mitochondrial Myopathies / Q000235:genetics / Q000503:physiopathology*; D009044:Motor Cortex / Q000502:physiology / Q000503:physiopathology*; D009046:Motor Neurons / Q000502:physiology; D009207:Myoclonus; D012016:Reference Values; D012684:Sensory Thresholds; D013003:Somatosensory Cortex / Q000502:physiology / Q000503:physiopathology*