Event-Related Potentials

Brain responses (i.e. evoked potentials) to psychological tasks are decomposed into independent components. The components are asso – ciated with distinctive psychological operations. Comparing the amplitude and latency of the components with the normative data gives new insights into the different stages of information processing in patients.

In clinical settings the HBI Database is a valuable resource for individualized treatment planning. An example of such an application is presented in Fig. 1. Simply viewing the raw EEG of an ADHD patient (top, left) does not reveal any abnormality; however, compression of the data into spectra and comparing the spectra with the normative data shows statistically significant (p<0.01) deviation from normality in the theta frequency range (top, right spectra) which is reflected in the central areas (see map at bottom). The electromagnetic tomography of the theta activity is presented at the bottom of the Figure. On the basis of these data, two alternatives of therapy are suggested for this patient:

  • psychostimulant medication such as Ritalin or Concerta and
  • training beta/theta ratio to correct inattention using the methodology of the brain computer interface (BCI).

Deviations from normality