Evaluation of the motor cortex by magnetic stimulation in patients with Alzheimer disease

A. Perretti, D. Grossi, N. Fragassi, B. Lanzillo, M. Nolano, A. I. Pisacreta, G. Caruso, L. Santoro

Research output: Contribution to journalArticlepeer-review


Motor evoked potentials (MEPs) from abductor pollicis brevis (APB) and tibialis anterior (TA) muscles elicited by transcranial magnetic stimulation of the motor cortex were studied in 15 patients with Alzheimer disease (AD). An abnormally higher MEP threshold in APB, frequently associated with absence of the MEP in relaxed TA muscles, was found in 40% of patients, almost all of them in the more severe stage of the disease. The MEP amplitude and averaged MEP/MAP ratio were reduced respectively by 20% and 26% in the APB muscle, and by 46.7% and 53.3% in the TA muscle. The less frequent prolongation of the central conduction time (CCT) (20%) might reflect preservation of the impulse propagation along the surviving pyramidal fibers. In 63.6% of the patients the central silent period (cSP) duration in the APB muscle was shortened; the mean value was significantly different between patients and controls. The results of this study suggest that loss and/or dysfunction of motor cortex neurones, including pyramidal cells and inhibitory interneurones may occur in AD patients before clinical signs become apparent.

Original languageEnglish
Pages (from-to)31-37
Number of pages7
JournalJournal of the Neurological Sciences
Issue number1
Publication statusPublished - 1996


  • Alzheimer disease
  • Motor cortex
  • Silent period
  • Transcranial magnetic stimulation

ASJC Scopus subject areas

  • Ageing
  • Clinical Neurology
  • Surgery
  • Developmental Neuroscience
  • Neurology
  • Neuroscience(all)


Dive into the research topics of 'Evaluation of the motor cortex by magnetic stimulation in patients with Alzheimer disease'. Together they form a unique fingerprint.

Cite this