title: Preserved transcallosal inhibition to transcranial magnetic stimulation in nondemented elderly patients with leukoaraiosis.
abstract: Structural corpus callosum (CC) changes in patients with leukoaraiosis (LA) are significantly associated with cognitive and motor impairment. The aim of this study is to investigate the transcallosal fibers functioning by means of transcranial magnetic stimulation (TMS) in elderly patients with LA. The resting motor threshold (rMT), the motor-evoked potentials (MEPs), and the controlateral (cSP) and ipsilateral silent periods (iSP) were determined using single-pulse TMS in 15 patients and 15 age-matched controls. The neuropsychological profile and the vascular burden at brain magnetic resonance imaging (MRI) were concomitantly explored. Patients reported abnormal scores at tests evaluating executive control functions. No significant difference was found in TMS measures of intra- and intercortical excitability. No CC lesion was evident at MRI. Transcallosal inhibitory mechanisms to TMS seem to be spared in LA patients, a finding which is in line with neuroimaging features and suggests a functional integrity of the CC despite the ischemic interruption of corticosubcortical loops implicated in cognition and behavior. The observed neurophysiological finding differs from that reported in degenerative dementia, even in the preclinical or early stage. In our group of patients, the pure extent of LA is more related to impairment of frontal lobe abilities rather than functional callosal changes.
authors.affiliation: G F Ingrassia Department, Section of Neurosciences, University of Catania, 78 Via Santa Sofia, 95123 Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lanza
authors.forename: Rita
authors.initials: R
authors.lastname: Bella
authors.forename: Salvatore
authors.initials: S
authors.lastname: Giuffrida
authors.forename: Mariagiovanna
authors.initials: M
authors.lastname: Cantone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pennisi
authors.forename: Concetto
authors.initials: C
authors.lastname: Spampinato
authors.forename: Daniela
authors.initials: D
authors.lastname: Giordano
authors.forename: Giulia
authors.initials: G
authors.lastname: Malaguarnera
authors.forename: Alberto
authors.initials: A
authors.lastname: Raggi
authors.forename: Manuela
authors.initials: M
authors.lastname: Pennisi
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003337:Corpus Callosum / Q000503:physiopathology*; D003704:Dementia / Q000503:physiopathology*; D003710:Demography; D005260:Female; D006801:Humans; D049292:Leukoaraiosis / Q000503:physiopathology*; D008297:Male; D009483:Neuropsychological Tests; D050781:Transcranial Magnetic Stimulation