Change in cognitive functions through physical training in schizophrenia - A controlled study

Aerobic exercise has been shown to improve symptoms in multi episode schizophrenia, including cognitive impairments, but results are inconsistent. Therefore, we evaluated the effects of an enriched environment paradigm consisting of bicycle ergometer training and add-on computer-assisted cognitive remediation (CACR) training. To our knowledge, this is the first study to evaluate such an enriched environment paradigm in multi episode schizophrenia. Twenty-two multi episode schizophrenia patients and twenty-three age and gender matched healthy controls underwent 3 months of endurance training (30min, 3 times/wk); CACR training (30min, 2 times/wk) was added from week 6. Twenty-one additionally recruited schizophrenia patients played table soccer (sometimes: foosball, table football) over the same period and also received the same CACR training. At baseline and after 6 weeks and 3 months, we measured cognitive domains with the Digit Span Test [DST], Verbal Learning Memory Test [VLMT], Regensburger Wortflüssigkeits Test [RWT], Trail Making Test [TMT] and Wisconsin Card Sorting Test [WCST]. The primary target variable was a total neuropsychological score for all three groups, composed of the individual variables of the test scores DST, VLMT, RWT, TMT and WCST. The evaluations for the secondary target variables, the individual test scores of DST, VLMT, RWT, TMT and WCST and the neuropsychological results used for these scores were explorative. The magnitude of the effects that should be detected has not been quantified. In the explicit individual review of the cognitive performance tests of the schizophrenic endurance group, compared after three months at baseline, no significant effect of aerobic endurance sport on specific cognitive deficits or dysfunctions could be demonstrated. Nonetheless, we were able to measure a positive effect of endurance sports with CACR training on the Short-Term Memory [STM] score comparing VMLT scores in the schizophrenia sports group at 6 weeks and 3 months. Interestingly, the STM score in the table soccer group also increased to baseline after 6 weeks, but not in the following 6 weeks, when the table soccer was combined with CACR. According to this, an additional effect of cognitive training on short term memory performance in combination with endurance sports can be assumed. In the evaluation of the total neuropsychological score, all three collectives improved significantly within 3 months. Overall, the healthy control group achieved significantly higher improvements over the course of 3 months compared to the two patient groups. This underpins the thesis of the suspected intact neuroplastic capacity in healthy people. Since the two patient groups did not differ in value improvements, it can be assumed that with reduced neuroplasticity, either the amount and duration of the selected endurance sport is insufficient to induce neuroplastic changes, or the group was too seriously impaired. In summary, the significant improvement in the total neuropsychological score in all three groups in our study suggests an overall positive effect of multimodal training, including endurance sports or skill training (table soccer) and cognitive training, on healthy individuals as well as on chronic schizophrenia patients. However, it remained unclear whether the improvement within the table soccer group was due to this intervention (training of attention, skill, responsiveness etc.), or rather non-specific effects such as motivation, social contact and improved day structure through the involvement of patients in such a study. In addition, our study shows that the adjuvant combination with a special cognitive training could bring about an improvement in memory performance. Accordingly, cognitive training adapted to the disease symptoms, combined with aerobic endurance training, could establish as a possible efficient add-on therapy in chronic schizophrenia. Consequently, our results should be validated with larger cohorts in randomized controlled clinical studies.2018-04-2