title: Measurements of transcallosally mediated cortical inhibition for differentiating parkinsonian syndromes.
abstract: Clinicopathologic evidence suggests differential involvement of cortex and corpus callosum (CC) in various disorders presenting with a parkinsonian syndrome. We tested the hypothesis of whether neurophysiologic and morphometric assessments of CC as surrogate parameters of cortical involvement could be helpful in differential diagnosis of parkinsonian disorders. The integrity of CC was assessed neurophysiologically by measuring the ipsilateral silent period (iSP) evoked by transcranial magnetic stimulation (TMS) in a total of 25 patients with idiopathic parkinsonian syndromes (IPS), corticobasal ganglionic degeneration (CBD), progressive supranuclear palsy (PSP), or multiple system atrophy (MSA). Additionally, morphometric analyses of magnetic resonance imaging (MRI) measurements of CC was carried out in all patients. iSP was abnormal in all 5 CBD and all 5 PSP patients, whereas it was intact in all 10 IPS patients and all 5 MSA patients. Among various MRI parameters of CC, testing between different groups revealed a significant difference only for measurements of the middle part of the truncus. CBD and PSP patients exhibited a significant atrophy as compared with control subjects. These data suggest impairment of callosal integrity in patients with CBD and PSP. iSP measurements may be a useful clinical neurophysiologic test in differential diagnosis of patients with parkinsonian syndromes.
authors.affiliation: Human Cortical Physiology Laboratory, Department of Neurology, University of Rostock, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Wolters
authors.forename: Joseph
authors.initials: J
authors.lastname: Classen
authors.forename: Erwin
authors.initials: E
authors.lastname: Kunesch
authors.forename: Annette
authors.initials: A
authors.lastname: Grossmann
authors.forename: Reiner
authors.initials: R
authors.lastname: Benecke
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001480:Basal Ganglia Diseases / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D003337:Corpus Callosum / Q000473:pathology* / Q000503:physiopathology; D003937:Diagnosis, Differential; D004576:Electromyography; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography / Q000379:methods; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology; D019578:Multiple System Atrophy / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology; D009410:Nerve Degeneration / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009433:Neural Inhibition / Q000502:physiology*; D020734:Parkinsonian Disorders / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D013494:Supranuclear Palsy, Progressive / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa