Fig. 1

Percentage of PD-patients (total) showing observed and significant improvements in cognitive performance after intervention compared to performance before. “Observed improvements” are seen in patients showing improvements in raw scores, indicating a trend, which, however, cannot be obtained statistically. “Significant improvements” are seen in patients who did show improvements calculated using the RCI method. Most patients showed unchanged cognitive performance (z score ≥ 1.645 to ≤ 1.645). A low proportion of patients showed non-significant improvements (z score ≤ 1.645) after intervention; The percentage of patients presenting with significant improvement (z score ≥ 1.645) after intervention was observed mainly in motor function and time-dependent tasks related to attention and executive functions. BDI-II, Beck’s depression inventory; MMSE Mini mental state examination, MoCA Montreal cognitive assessment; SCOPA-PS Scales for outcomes in Parkinson's disease—Psychosocial questionnaire, UPDRS Unified Parkinson’s disease rating scale. Overview composites: see Table 2)