EEG study of visual reactivity in aphasic patients

To compare patients with good and poor recovery after 1 and 3 months from onset of poststroke aphasia and to correlate the quality of recovery with quantitative EEG (QEEG) measures (frequency analysis with the limits of variability, and index of asymmetry).

The investigation was performed on the sample of 32 patients with poststroke aphasia, 15 females (46.88%) and 17 males (53.12%), mean age +/- standard deviation (SD) being 50.65 +/- 9.93 years. QEEG measures of this sample were compared with those in a group of 86 healthy controls, 39 (45.35%) females and 47 (54.65%) males, mean age +/- SD being 51.08 +/- 10.08 years. Frequency analysis was performed in eyes closed and eyes open conditions in both controls and in aphasics who were tested just before and two month after rehabilitative treatment with speech therapy.

We have got normal distribution for all derivations and all frequency bands in the group of healthy subjects. On the basis of this finding, we determined coefficients of variation in patients with poststroke aphasia and discovered that their maximal variability scores were significantly decreased. Compared to healthy subjects, the index of asymmetry between two hemispheres and between main brain regions was significantly higher in the aphasic patients than in controls. However, the differences in the index of asymmetry and limits of variability significantly decreased after two month treatment in the subgroup of patients with good improvement compared with the subgroup of patients with poor improvement of poststroke aphasia.

QEEG measures may have predicitive value in post-stroke aphasia.