Effective rehabilitation is an integral part of the recovery process and regaining independence of patients after a stroke. Unfortunately, many factors hinder this process. One of them may be cognitive disorders25,26,27.
The comparison of the studied groups of patients with different cognitive functions at the time of admission to the ward (T1) showed no significant differences in demographic variables. Still, there were significant differences in the time from stroke and the length of stay in the ward. At the time of admission, patients without CI were characterized by a significantly shorter time elapsed since the stroke and a substantially longer length of stay in the rehabilitation ward compared to patients with dementia. Similar results were reported by Kowalska et al.28. Also, Tornes et al. showed that dementia influences the patient's acute hospital length of stay29. According to Liu et al., dementia was the most notable length of stay-specific and cost-specific comorbidities among patients after stroke30.
The assessment of the functional status of the examined patients showed a significantly worse functional status of patients with moderate dementia compared to patients without cognitive impairment both at the time of admission to the ward and at the time of discharge. Differences in functional status between the groups were more pronounced at the time of discharge, and also included patients with mild dementia. In the studies of Sawyer et al., CI patients were more likely to experience withdrawal of care during hospitalization, and for survivors, had greater disability and lower BI scores, especially after hemorrhagic stroke31. In addition, at the time of discharge from the ward, patients with moderate dementia were characterized by significantly worse balance compared to patients without cognitive dysfunction. As in the studies of Whitney et al., the chances of a fall are higher in patients after a stroke with co-existing dementia32.
In fact, the results regarding the functional state do not differ from the reports of other authors who emphasize that the occurring disorders of cognitive functions in patients after a stroke (post-stroke dementia) are the cause of addiction and disability33. It is also an important reason for the poor prognosis in patients after stroke with motor and speech dysfunction27. According to Lee et al., CI after stroke can increase the limitations of activity of daily living. Patients after a stroke with CI had the highest prevalence of disabilities in basic and instrumental activities of daily living1. However, the author points out that the inability to perform certain activities may result from paresis, not CI.
It is worth mentioning that the most remarkable and significant improvement in functional status and patient static and dynamic balance was observed among patients without cognitive impairment and patients with MCI. In the group of patients with moderate dementia, this improvement concerned only the SAS-hand function. This group of patients also stayed in the ward for the shortest time. Perhaps the lack of visible progress, especially in terms of self-care, and the lack of favorable prognosis resulted in a faster discharge from the rehabilitation ward. Unfortunately, this is a common situation noted, for example, by Mizrahi et al.25. Patients with dementia derive less benefit from standard rehabilitation, and failure to take into account the cognitive state by medical staff additionally hinders the rehabilitation process. It affects the final results of the patient's stay in the ward. This patient group is often transferred to long-term care centers after early rehabilitation. This is confirmed by the studies of Sibolt et al., in which the authors emphasize that post-stroke dementia is associated with shorter survival time and earlier permanent institutionalization compared to patients without post-stroke dementia34.
Nevertheless, further results (TUG test analysis) showed that also this group of patients (with CI and dementia) could be successful. The analysis of the TUG test showed that 19 out of 94 patients with dementia were unable to perform the TUG test in this group at the time of discharge. In contrast, in the initial test, the inability to perform the test was observed in as many as 62 people. Also, the results of Kowalska et al. indicate the possibility of improving the functional status in this group of patients10.
However, this requires a longer time and, unfortunately, does not guarantee a return to full functional efficiency. And even then, the occurring symptoms of dementia at the intermediate level are a premise for implementing more care on the part of caregivers or providing institutional care.
Therefore, knowledge of the cognitive state of patients after a stroke may be the key to more effective rehabilitation. Setting realistic goals by the medical staff and using modified therapeutic procedures adapted to the patient's cognitive abilities after a stroke may translate into a rehabilitation outcome.
The regression results also confirm this. In the present study, the MMSE and BI scores at admission to the ward and also the MMSE score at T2 explained as much as 43% of the functional status at discharge. This confirms that cognitive functions and functional status of stroke patients (at admission to the ward) are predictors of functional status at discharge. Assuming that the result of effective rehabilitation is the improvement of the functional state of patients after a stroke, it can be concluded that their state of cognitive functions determines the effectiveness of rehabilitation.
It is also worth emphasizing the dynamics of changes in cognitive functions in patients after a stroke. The obtained results indicate an improvement in the cognitive state of the examined patients at the time of discharge from the ward. Nevertheless, Mijajlowić et al. point out that cognitive impairment is gradually deteriorating despite a greater or lesser improvement in the functional status of patients after a stroke6. Therefore, this condition should be systematically monitored and included in the assessment of all results of clinical trials on strokes, and activities related to primary or secondary prevention of dementia should be implemented35.
Even though Gallucci and Umarova state that it is impossible to reliably identify patients at risk of post-stroke cognitive dysfunction because many factors worsen cognitive performance after stroke36, previous studies show the effectiveness of introduced cognitive and functional training5,7,37,38. Interventions aimed at the secondary prevention of dementia and the improvement of motor skills may also reduce the risk of falls in people after stroke32.
To sum up: The presented research results indicate a significant relationship between patients' cognitive and functional status after stroke. Therefore, in the holistic model of rehabilitation of patients after a stroke, the cognitive state should also be considered in the entire rehabilitation and treatment process.
Limitations. The authors are aware of some limitations of the presented studies. First, the division into groups was based on a screening test, not a diagnosis. We do not know the cognitive state of the pre-stroke period. Although one of the exclusion criteria from the study was the presence of pre-stroke dementia, it cannot be ruled out that such symptoms had already occurred before but were not diagnosed. It is a single-centre study, so the results must be interpreted cautiously for other populations.