title: Motor cortex excitability in Alzheimer's disease and in subcortical ischemic vascular dementia.
abstract: Twenty Alzheimer's disease (AD) patients, 20 subcortical ischemic vascular dementia (SIVD) patients and 20 neurologically and cognitively normal subjects underwent transcranial magnetic stimulation to study motor cortex excitability changes. Motor threshold (MT), amplitude of motor evoked potentials, silent period and the H/M ratio (amplitude of maximal Hoffman reflex vs. that of maximal motor response) were considered. MT was lower in SIVD patients when compared with AD patients (P = 0.003) and the control group (P < 0.001) and lower in AD patients when compared with the control group (P < 0.001). The increment of motor cortex excitability in AD and SIVD did not lead us to distinguish clearly the two types of dementia. It is likely that the electrophysiological similarity between AD and SIVD could represent another common mechanism shared from these forms of dementia.
authors.affiliation: Department of Neurological Sciences, University of Catania, Catania, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Alagona
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ferri
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pennisi
authors.forename: Anna
authors.initials: A
authors.lastname: Carnemolla
authors.forename: Tiziana
authors.initials: T
authors.lastname: Maci
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Domina
authors.forename: Alain
authors.initials: A
authors.lastname: Maertens de Noordhout
authors.forename: Rita
authors.initials: R
authors.lastname: Bella
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology*; D015140:Dementia, Vascular / Q000503:physiopathology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*