Effects of theta burst stimulation on cognitive function and characteristics of blood oxygen alterations based on near-infrared spectroscopy in chronic schizophrenia.

BACKGROUND

To explore the efficacy of theta burst stimulation (TBS) on the cognitive function of chronic schizophrenia, and to analyze the effect of TBS on brain function using functional near-infrared spectroscopy (fNIRS).

METHODS

One hundred stable chronic schizophrenia patients were selected and divided randomly into the experimental group (50 cases) and control group (50 cases). The experimental group received real TBS stimulation to the left dorsolateral prefrontal cortex (DLPFC) for 4 weeks, while the control group received sham stimulation to the same site. The Mini-mental State Examination (MMSE) and Mattis-dementia Rating Scale Second Edition (MDRS-2) were used to assess cognitive function. fNIRS was used to detect the changes in hemoglobin signal values during the verbal fluency task (VFT) before and after TBS intervention.

RESULTS

Repeated measures analysis of variance showed that the interaction effect of group-by-time had a significant impact on MMSE, MDRS-2 total scores, MDRS-2 attention, MDRS-2 initiation/sustain, MDRS-2 concept formation, and MDRS-2 memory subscale scores for both groups of patients. Tests of within-subjects effects showed that significant improvements in MMSE, MDRS-2 total scores, MDRS-2 attention and memory subscale scores were found between the experimental group and control group after TBS, as well as in the experimental group before and after TBS. Multiple factor stepwise regression analyses found that the improvement of MDRS-2 total scores after the intervention was positively correlated with age in the experimental group. Based on fNIRS-VFT, the experimental group showed significant decrease in deoxyhemoglobin signal values in channel 47 (left dorsolateral prefrontal cortex) before and after the intervention.

CONCLUSIONS

TBS may have the potential to improve brain activity by enhancing the blood oxygen consumption of the stimulation target, as indicated by the fNIRS findings. Then, it may contribute to improvements in cognitive function of patients with chronic schizophrenia. However, the age of the patients may be an independent factor influencing the prediction of the treatment effect.