Alpha rhythms in mild dements during visual delayed choice reaction time tasks: A MEG study

Claudio Babiloni, Emanuele Cassetta, Paola Chiovenda, Claudio Del Percio, Matilde Ercolani, Davide Vito Moretti, Filomena Moffa, Patrizio Pasqualetti, Vittorio Pizzella, Gian Luca Romani, Franca Tecchio, Filippo Zappasodi, Paolo Maria Rossini

Research output: Contribution to journalArticlepeer-review


Can simple delayed response tasks affect latency and amplitude of magnetoencephalographic midline alpha rhythms (6-12 Hz) in early dementia? We recruited 15 mild Alzheimer's disease (AD) and 10 vascular dementia (VaD) patients (paired mini mental state exam of 17-24). The control groups comprised 18 young and 22 elderly normal subjects. In the first task, a simple "cue" stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s) up to a "go" stimulus triggering (right or left) button press. In the second task, the "cue" stimulus remained available along the delay period. Event-related reduction in power of the alpha rhythms indexed the cortical activation (event-related desynchronization, ERD) for the trials associated with correct behavioral responses. Behavioral performances to both tasks were lower in the AD and VaD patients than in the normal subjects. In particular, just four AD and five VaD patients executed a sufficient amount of correct responses for the alpha ERD analysis, so they were included in a unique group. In both tasks, the alpha ERD peak was later in latency in the demented and normal elderly subjects than in the normal young subjects. Furthermore, the alpha ERD peak was stronger in amplitude in the demented patients than in the normal subjects. These results suggest that simple delayed response tasks during physiological recordings are quite difficult for patients even at an early dementia stage. Such difficulty may induce the abnormal amount of the related cortical activation in dementia as revealed by the alpha ERD.

Original languageEnglish
Pages (from-to)457-470
Number of pages14
JournalBrain Research Bulletin
Issue number6
Publication statusPublished - May 30 2005


  • Alpha event-related desynchronization (ERD)
  • Delayed response task
  • Magnetoencephalography (MEG)
  • Mild Alzheimer's disease (AD)
  • Vascular dementia (VaD)

ASJC Scopus subject areas

  • Neuroscience(all)


Dive into the research topics of 'Alpha rhythms in mild dements during visual delayed choice reaction time tasks: A MEG study'. Together they form a unique fingerprint.

Cite this