Background: Based on the theory of postural control and the role of cognitive capacity, this study analyses how physical ability and somatosensory impairment influence affective symptoms in patients with stroke.
Methods: The cross-sectional study with a consecutive sampling approach was conducted in 10 different rehabilitation departments in Yunnan Province, China between August 2019 and February 2021. A total of 1,058 patients with stroke were included according to the inclusion criteria and exclusive criteria. Their important functions were evaluated including somatosensory measurement, Brunnstrom recovery stage, manual muscle testing (MMT), Barthel index (BI), mini-balance evaluation systems test (Mini-BEST), Montreal Cognitive Assessment (MoCA), Hamilton Anxiety Scale (HAM-A), and Hamilton Depression Scale (HAM-D). Exploratory Factor Analysis was used to construct the measure models. A path analysis was performed to estimate the role of balance impairment and cognitive capacity as mediators in the relationships between somatosensory impairment, physical ability and affective symptoms.
Results: By comparing two models, the final model indicated a good global model fit to the data [χ2=243.5, χ2/df=5.181, goodness-of-fit index (GFI) =0.977, comparative five index (CFI) =0.944, Tucker-Lewis index (TLI) =0.922, standardized root mean square residual (SRMR) =0.063, and root mean square error of approximation (RMSEA) =0.063, Akaike information criterion (AIC) =303.51, Bayesian information criterion (BIC) =304.26], although Chi-square test was not significant due to the large sample size. In the path analysis, somatosensory impairment significantly negative influenced balance impairment (P<0.05, β=-0.061), and physical ability significantly positively affected balance impairment (P<0.001, β=0.893). A mediation analysis was conducted to show that balance impairment mainly mediated the relationship between physical ability and affective symptoms (R2=0.996), while the relationship between physical ability and affective symptoms was mediated slightly by cognitive capability (R2=0.108).
Conclusions: These results suggest that balance impairment mainly mediates the relationship between physical ability and affective symptoms, while cognitive capacity slightly medicates this relationship. Rehabilitation professionals and family caregivers should pay more attention to balance function, which will help to strengthen the physical ability and improve post-stroke mood disorders.
Keywords: Mediation analysis; balance; cerebrovascular disease; mood.