OBJECTIVES: To evaluate the activity of cortico-cortical (intracortical) inhibitory circuits within the motor cortex in patients with progressive asymmetric limb-kinetic apraxia. MATERIALS AND METHODS: We studied 4 patients with progressive limb-kinetic apraxia whose clinical diagnosis was corticobasal degeneration (CBD) and 7 control subjects. Cortico-cortical inhibition was measured using the technique of double pulse transcranial magnetic stimulation over the motor cortex. The effects of conditioning stimuli on the test responses were examined. RESULTS: In the normal control subjects, the conditioning magnetic stimulus suppressed motor evoked responses to the test stimulus at interstimulus intervals of 1 to 5 ms. This inhibition was significantly diminished on the affected side of the patients, but it was normal on the less affected side. CONCLUSION: Disruption of intracortical inhibitory circuits in the motor cortex may, at least in part, be related to severe limb clumsiness in the patients with progressive limb-kinetic apraxia.
OBJECTIVES: To evaluate the activity of cortico-cortical (intracortical) inhibitory circuits within the motor cortex in patients with progressive asymmetric limb-kinetic apraxia. MATERIALS AND METHODS: We studied 4 patients with progressive limb-kinetic apraxia whose clinical diagnosis was corticobasal degeneration (CBD) and 7 control subjects. Cortico-cortical inhibition was measured using the technique of double pulse transcranial magnetic stimulation over the motor cortex. The effects of conditioning stimuli on the test responses were examined. RESULTS: In the normal control subjects, the conditioning magnetic stimulus suppressed motor evoked responses to the test stimulus at interstimulus intervals of 1 to 5 ms. This inhibition was significantly diminished on the affected side of the patients, but it was normal on the less affected side. CONCLUSION: Disruption of intracortical inhibitory circuits in the motor cortex may, at least in part, be related to severe limb clumsiness in the patients with progressive limb-kinetic apraxia.
Authors: F Mastrolilli; A Benvenga; L Di Biase; F Giambattistelli; L Trotta; G Salomone; L Quintiliani; D Landi; J M Melgari; F Vernieri Journal: Int J Alzheimers Dis Date: 2011-07-12