Multiparametric asymmetry score (MAS)--distinction between normal and ischaemic brains.

A multiparametric asymmetry score (MAS) is presented. It is based on the EEG data of 50 normal subjects and 32 patients with cerebral ischaemia. For the asymmetry measurements, the following parameters appeared to be the most powerful in the given order: the ratio theta/beta power, the peak frequency, absolute delta and theta powers and the ERD in the alpha band. The EEG data were recorded during rest and during voluntary hand movements from the centro-temporal regions. As the MAS can be calculated with or without the peak frequency parameter, it is applicable to all types of EEG data. Using the MAS, 94% of the normal and 92% of the patient data were correctly classified. From the patient group, 6 were without neurological deficits and 9 had 'normal' clinical EEGs.