Therapeutic effects of individualized alpha frequency transcranial magnetic stimulation (alphaTMS) on the negative symptoms of schizophrenia

Abstract

Previous research in clinical electroencephalography (EEG) has demonstrated that reduction of alpha frequency (8-13 Hz) EEG activity may have particular relevance to the negative symptoms of schizophrenia. Repetitive Transcranial Magnetic Stimulation (rTMS) was utilized to investigate this relationship by assessing the therapeutic effects of stimulation set individually at each subject's peak alpha frequency (alphaTMS). Twenty-seven subjects, with predominantly negative symptom schizophrenia, received 2 weeks of daily treatment with either alphaTMS, 3 Hz, 20 Hz, or sham stimulation bilaterally over the dorsolateral prefrontal cortex. Individualized alphaTMS demonstrated a significantly larger (F (3,33) = 4.7, p = .007) therapeutic effect (29.6% reduction in negative symptoms) than the other 3 conditions (< 9%). Furthermore, these clinical improvements were found to be highly correlated (r = 0.86, p = .001) with increases (34%) in frontal alpha amplitude following alphaTMS. These results affirm that the resonant features of alpha frequency EEG play an important role in the pathophysiology of schizophrenia and merit further investigation as a particularly efficacious frequency for rTMS treatments.

Figures

Fig. 1

Clinical response to rTMS at 3 Hz (n = 9), 20 Hz (n = 9), alpha frequency (n = 11), and sham (n = 8) immediately following 2 weeks of treatment (Week 2) and after an additional 2 weeks following end of treatment (Week 4). The level of response is shown as percent decrease (improvement) from baseline Positive and Negative Syndrome Scale (PANSS) negative symptom subscale scores.

Fig. 2

Percent improvements in the Positive and Negative Syndrome Scale (PANSS) negative symptom subscale were significantly correlated with changes in the alpha band (α: 8–13 Hz) EEG in the frontal cortex of those patients receiving the individualized αTMS. Such correlations were not found for any of the other treatment groups or cortical regions examined.