title: [Progressive limb-kinetic apraxia with myoclonus focal atrophy in the postcentral gyrus and the supplementary motor area].
abstract: We report a 70-year-old right handed man with a 5-year history of slowly progressive clumsiness of his left hand. A neurological examination disclosed mild rigidity and myoclonus in his left hand. He showed limb-kinetic apraxia, but neither ideational apraxia nor ideomotor apraxia was present. Aphasia and agnosia were also absent. He was thought to have the primary progressive limb-kinetic apraxia clinically. Brain CT and MRI revealed focal atrophy in the right postcentral gyrus and the supplementary motor area. A positron emission tomography (PET) study showed diffuse decrement of cerebral blood flow, predominantly in the right hemisphere. The decrease in the uptake of [18F]-Fluoro-deoxyglucose also revealed glucose hypo-metabolism, especially in the right frontal and parietal lobe. Striatal [11C]NMSP and [18F]FDOPA uptake were also reduced in an asymmetric pattern. These findings suggest that our patient is likely to have corticobasal degeneration. Transcranial magnetic stimulation using double pulse paradigm revealed a decrease in the level of cortico-cortical inhibition in the motor cortex on the affected side. Our results indicate increase in the excitability of motor cortical neurons in primary progressive limb-kinetic apraxia, likely due to a decreased excitability of cortico-cortical inhibitory mechanism as a result of focal degeneration of cortical neurons.
authors.affiliation: Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishiwata
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Y
authors.initials: Y
authors.lastname: Okuma
authors.forename: K
authors.initials: K
authors.lastname: Mitani
authors.forename: Y
authors.initials: Y
authors.lastname: Mizuno
mesh_terms: D000368:Aged; D001072:Apraxias / Q000503:physiopathology*; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D004576:Electromyography; D005073:Evoked Potentials, Somatosensory; D005121:Extremities / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D008297:Male; D009207:Myoclonus / Q000150:complications*; D009410:Nerve Degeneration