Introduction and objective:
The aim of the study was to evaluate the peripheral level of brain-derived neurotrophic factor (BDNF) and matrix metalloproteinase-9 (MMP-9) during rehabilitation therapy, combined with neurofeedback in schizophrenic patients, and to investigate whether these biomarkers are related to psychopathological symptoms, changes in auditory evoked potentials (AEPs), and quantitative EEG (QEEGs) mapping.

Material and methods:
The study involved two groups of patients diagnosed with paranoid schizophrenia in partial remission who participated in a 3-month structured rehabilitation programme combined with neurofeedback (REH group) and a standard support group (CON group). The following parameters were assessed: BDNF and MMP-9 serum levels, AEPs, QEEGs, and psychopathological symptoms (PANSS).

A clinical improvement within the 3-month rehabilitation therapy course was correlated with the increase in BDNF and MMP-9 serum level. Despite the increase in BDNF and MMP-9 during the 3-month rehabilitation therapy, it was not possible to demonstrate any strong and significant correlation between the 2 examined neuropeptides. During the 3-month rehabilitation therapy, the theta waveform share reduction in QEEG, P50 latency reduction and amplitude increase correlated with PANSS Total and MMP-9 results.

All clinical (PANSS Positive, Negative, General, Total) and biochemical results (BDNF, MMP-9) of the REH group changed significantly over the 3-month period. Positive symptoms improved only in the CON group.

AEPs – auditory evoked potentials; BDNF – brain-derived neurotrophic factor; CNS – central nervous system; DC – direct current; EEG – electroencephalogram; GSR – galvanic skin response; ICD – international classification of diseases; MMP- 9 – matrix metalloproteinase-9; NF – neurofeedback; NPS – neuropeptide S; PANSS – positive and negative syndrome scale; SCL – skin conductance level; SCRs – skin conductance responses; TIMP – tissue inhibitor of metalloproteinease-9; QEEG – quantitative electroencephalogram
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