Combining transcranial magnetic stimulation with training to improve social cognition impairment in schizophrenia: a pilot randomized controlled trial

Abstract

Schizophrenia is a severe, chronic mental disorder that profoundly impacts patients' everyday lives. The illness's core features include positive and negative symptoms and cognitive impairments. In particular, deficits in the social cognition domain showed a tighter connection to patients' everyday functioning than the other symptoms. Social remediation interventions have been developed, providing heterogeneous results considering the possibility of generalizing the acquired improvements in patients' daily activities. In this pilot randomized controlled trial, we investigated the feasibility of combining fifteen daily cognitive and social training sessions with non-invasive brain stimulation to boost the effectiveness of the two interventions. We delivered intermittent theta burst stimulation (iTBS) over the left dorsolateral prefrontal cortex (DLPFC). Twenty-one patients were randomized into four groups, varying for the assigned stimulation condition (real vs. sham iTBS) and the type of cognitive intervention (training vs. no training). Clinical symptoms and social cognition tests were administered at five time points, i.e., before and after the treatment, and at three follow-ups at one, three, and six months after the treatments' end. Preliminary data show a trend in improving the competence in managing emotion in participants performing the training. Conversely, no differences were found in pre and post-treatment scores for emotion recognition, theory of mind, and attribution of intentions scores. The iTBS intervention did not induce additional effects on individuals' performance. The methodological approach's novelty and limitations of the present study are discussed.

Keywords: DLPFC; TMS; iTBS; schizophrenia; social cognition.

Figure 1

The CONSORT flowchart (Schulz et al., 2010) includes the number of participants in each group and phase.

Figure 2

The figure depicts the emotional intelligence scores (MSCEIT) at the different time points. The boxplots represent the comparison between real iTBS (dark gray boxes) and sham iTBS (light yellow boxes) separately for the no training and training conditions.

Figure 3

The figure represents the effects on the facial expression recognition score (FEIT). On the left panel, data trend for the real iTBS (dark gray boxes) and sham iTBS (light yellow boxes) at the different time points is reported. On the right panel, the graph shows performance at FEIT at the different time points.

Figure 4

The figure shows the correlation matrix depicting the relationships between each pair of variables at the baseline. Positive correlations are blue-colored, and negative correlations are red-colored. Dots’ color intensity and size are proportional to the correlation coefficients, and asterisks inside the dots represent the statistical significance (*p < 0.05, **p < 0.01, ***p < 0.001). Note: BNSS = Brief Negative Symptoms Scale; CDSS = Calgary Depression Scale for Schizophrenia; CGI = Clinical Global Impression; PANSS_NEG = negative symptoms measured at Positive and Negative Syndrome Scale (PANSS); PANSS_POS = positive symptoms measured at PANSS; PANSS_PSYCHO = general psychopathology measured at PANSS; SLOF = Specific Level of Functioning; WHOQOL_QUAL = World Health Organization Quality of Life Assessment – quality score; WHOQOL_PSY = World Health Organization Quality of Life Assessment – psychological well-being.