MThe majority of patients in the acute phase after stroke demonstrate reduced upper limb (UL) mobility [1]. In more than a half of stroke patients, UL motor deficit can be observed in the chronic phase [2,3]. To compare, 80% of patients regain gait ability [4,5]. It is not clear where this disproportion stems from. Is it conditioned by greater movement complexity or by improper therapy? Currently, the need for commencing physical therapy in the first days following stroke is no longer questioned. An early post-stroke stage is significant in terms of predicting further UL improvement [6]. However, the existing procedures do not provide detailed guidelines regarding UL rehabilitation model particularly in the first four weeks after stroke. In clinical practice, too little attention is paid to UL training in the early post-stroke period [4]. It is hard to estimate neurobiological limitations related to UL mobility improvement and what the effectiveness of UL therapy is. Therefore, the question arises whether the current model of early post-stroke rehabilitation used in clinical practice both in Poland and abroad is sufficient.
This study sought to identify the most important problems regarding early UL stimulation in stroke patients.
Although UL functional recovery patterns differ depending on a patient, it can be stated that UL functional improvement up to the 6th month is highly predictable [7,8]. The pace of improvement is the highest in the first four weeks. After that, it gradually decreases and after six months from stroke onset, improvement is still possible yet much less likely [9,10].
When it comes to different significant predictors of UL recovery, the literature of the subject most commonly distinguishes two factors of the highest prognostic value, i.e. early UL motor and functional assessment as well as the presence of motor-evoked potentials and somatosensory-evoked potentials [6]. Assessment of the initial severity of motor impairment following stroke correlates with the degree of further motor recovery. The worse the motor performance at an initial stage (in the first days after stroke), the worse the prediction. For instance, the presence of active shoulder and finger movements within 7 days after stroke strongly correlates with further UL functional recovery [7]. The presence of any finger extension within 72 hours after stroke onset predicts greater UL recovery at 6 months. No voluntary finger extension reduces recovery likelihood [8]. Apart from UL functional examination, assessment of motor-evoked potentials and somatosensory-evoked potentials improves prognostic accuracy [6,11]. Unfortunately, its application in clinical practice is currently too expensive but it remains a good research tool.
Despite ongoing rehabilitation, the pace of upper limb neurological and functional improvement rapidly decreases in the course of time from stroke onset. It seems highly likely that neurophysiological recovery mechanisms observed within the first four weeks from stroke which accompany spontaneous functional recovery of UL are particularly significant in terms of UL motor improvement [7,12]. This period is linked to the greatest dynamics of neuroplastic changes induced by altered activity of genetic growth factors, increased angiogenesis as well as penumbra reperfusion [7,12,13]. UL neurobiological recovery occurs on the basis of two mechanisms. The first one is the mechanism of nervous tissue healing that helps to regain proper nervous functions. It makes it possible for motor functions to return to their natural model. The second one is the mechanism of neuroplastic reorganisation, i.e. enhancement of synaptic connections. On a neuronal level, it allows for the compensation of the lost functions, while on a behavioural level, it results in the changed compensatory or adaptive kinematic model. The course of neuroplastic changes that depend on environmental stimuli may exert either a positive or negative influence on UL functional recovery based on the adaptation to altered conditions [12,13]. Neurophysiologists put forward a hypothesis that the restitution of nervous functions observed in the first weeks following stroke may only be hampered by compensatory mechanisms that are active in the early phase and later [12].
The difference between these two mechanisms is the most evident when it comes to motor task performance, i.e. qualitative features of movement. Recent investigations on the kinematic model of arm functional recovery have revealed that the quality of movement may be crucial for UL functional improvement outcome. Kinematic studies of movement pattern formation immediately after stroke highlight the fact that motor control normalization in the recovery process is expressed through an increase in the number of controlled degrees of freedom, as is the case of healthy individuals in the same age group [14]. Another biomechanical investigation [15] revealed that motor control normalization of the paretic UL is closely connected with an increase in peak velocity, movement smoothness, precision of intended movement, positioningrelated error reduction, compensation minimisation by a scapula and torso as well as co-movement of an elbow and shoulder when performing a reaching movement. From a biomechanical standpoint, it is most beneficial (regardless of neurobiological mechanisms) to try to recreate UL pattern that would be as similar as possible to the natural one [12]. A compensatory pattern created on the basis of greater involvement of the ipsilateral hemisphere and other nervous structures seen in the MRI examination is certainly less effective. Smaller movement selectivity leads to a decrease in the degrees of freedom of the kinematic chain, a reduction in movement velocity and an increase in proximal control contribution (shoulder, torso). In the case of the mechanism of UL motor improvement in the first days after stroke, recovery processes that last up to the 10th week prevail and later they are followed by compensation and adaptation. There is strong evidence that neurobiological processes that help to maintain motor control quality are limited to the first three months of spontaneous neurological recovery [7,12]. However, the limitation of these studies is that they focused on patients receiving physiotherapy in typical doses and it was not intensive. This therapeutic window corresponds with the model of increased expression of genetic growth factors responsible for brain recovery processes in animals after cerebral ischemia. Great dynamics of UL motor function improvement indicates that it is based on neuroplasticity mechanisms that are most active in a period of spontaneous functional recovery. Therefore, UL physiotherapy should definitely begin in the first days following stroke. Its quality and quantity ought to make full use of neuroplastic potential of the brain [12].
Early mobilization after stroke is considered to be a significant element of multidisciplinary stroke unit care and its model mainly involves making the patient assume an erect position and acquiring basic motor skills such as rolling over, sitting, standing up and walking [16]. In clinical practice, upper limb physiotherapy receives the least attention [4]. In Poland, recommendations regarding rehabilitation procedures are outlined by the guidelines of the Vascular Expert Group of the Polish Neurological Society from 2012 [17]. According to the guidelines, motor mobilization of patients should take place as early as possible. From the beginning, physiotherapy ought to be oriented at regaining the lost functions. Physical therapists should make use of various physiotherapeutic methods and select the ones that would be the most effective for a particular patient. Despite considerable motor deficits, patients should be encouraged to take up proper and independent physical activity and they should take part in physiotherapy of adequate intensity and duration. Persons who tolerate effort similar to the normal one ought to be included in the programme of intensive rehabilitation (at least 3 hours of exercises daily). Physiotherapy should be based on the rules of effective learning and it should take place a few times a day. Moreover, patients’ needs and capabilities ought to be taken into consideration and exercises ought to be implemented in everyday activities. The goals of physiotherapy should be individualised and oriented at improvement on the levels of structure and function (e.g. selective arm movements should be reproduced) and on the levels of activity and participation (reference to everyday activities) [17,18]. The guidelines also recommend that motor re-education of the patient be performed in high positions, i.e. when sitting and standing. From the very beginning, patients should be encouraged (within their capacities) to take active part in rehabilitation. Also, they should be motivated and informed about physiotherapy goals. Their family and guardians should get involved in cooperation as well [3].
The guidelines of the Vascular Expert Group of the Polish Neurological Society that refer to early post-stroke period are not detailed enough in terms of UL rehabilitation and they only constitute a certain procedural framework [17].
There is a scarcity of data on UL physiotherapy at an early stage after stroke, particularly within the first three weeks from stroke onset. Clinical standards have not been developed yet and they do not constitute everyday clinical work. To the best of our knowledge, in Poland there have not been any investigations concerning the state of early post-stroke rehabilitation including UL therapy. International guidelines for post-stroke procedures highlight the need for intensive and continuous rehabilitation already at the acute phase [19]. The research on animal models showed that UL functional improvement enhanced by reorganisation and broadening of the motor cortex maps is possible if training based on physical activity is introduced and patients perform at least 400 repetitions [20–22]. Even though the amount of exercises based on motor task training seems to be a decisive factor contributing to the success of post-stroke UL therapy, in clinical practice UL exercise intensity is debatable [23]. Clinically implemented amount of exercises, understood as the duration of therapeutic sessions and the number of repetitions, as well as the type of motor exercises are not known.
Hayward and Brauer [4] performed a systematic review based on an in-depth analysis of literature regarding therapeutic dose (time and number of exercise repetitions) of UL training that mainly involves physical activity in the acute and subacute phases after stroke. Out of more than 3,000 publications, only 10 studies that met the aforementioned selection criteria and the criteria of evidence-based practice (EBP) were selected [4]. In their study (n=58), Bernhardt J. et al. tried to determine mean time of arm activity during one therapeutic session. In the centres included in the study, average session times were 24 minutes for physiotherapy and 23 minutes for occupational therapy. As for the duration of UL active motor therapy, 5-6 days from stroke onset it lasted an average of approx. 4 minutes during one session (17% of the whole therapeutic session) and approx. 11 minutes during an occupational therapy session (49% of the whole therapeutic session) [23]. In the Finnish study by Peurala et al., it was noted that on average 8 days post stroke, patients (n=19) received 6 minutes of UL training per session (15% of a therapeutic session) [24,25]. Australian reports (n=32) concerning patients (an average of 40 days post stroke) revealed the lack of UL activity during physiotherapy [26]. In occupational therapy, UL involvement in motor tasks lasted 29 minutes (70% of a therapeutic session). Another study showed that approx. 1 minute was devoted to UL therapy (2% of a therapeutic session) [27]. In turn, the Dutch research revealed that early post-stroke UL rehabilitation lasted an average of approx. 8 minutes per day (21% of the total duration of physiotherapeutic sessions) and 37 minutes per day in the case of occupational therapy [28]. To compare, the findings of four studies (n=4) showed that stroke patients in the subacute phase received an average of 4 minutes (0.9 to 7.9) of active UL exercises per one therapeutic session, which accounted for 2% to 10% of the total duration of one session. In turn, UL motor tasks performed during one occupational therapy session took 17 minutes (9.3 to 28.9), which constituted 23% to 70% of one exercise session [29,30].
There are no reliable investigations that determine the dose in the form of the number of motor task repetitions in a therapeutic session in the acute phase after stroke [29]. Only two meta-analytic studies revealed the number of activity-related arm repetitions in the subacute phase after stroke (23 and 32 repetitions) [30] during physiotherapy and occupational therapy [29]. Recently, two independent investigations have revealed that during a onehour session stroke patients in the subacute phase are capable of performing between 251 and 281 various motor activities related to their paretic UL [31,32]. There are no Polish studies on a therapeutic dose of activity-related UL exercises (including an arm) in physiotherapy and occupational therapy interventions in a period of the first four weeks after stroke and later.
A number of scientists are inclined to believe that it is not a specific physiotherapeutic method that enhances therapy effectiveness but properly individualised physiotherapeutic interventions adjusted to particular deficits and needs of a patient. Modern physiotherapeutic methods are mainly based on reproducing motor functions, i.e. trying to return to a pre-stroke state as much as possible [33,34]. This approach focuses on striving, as far as possible, to perform activities in the same way and with the same effectiveness and efficiency as before stroke. This strategy seems to be particularly significant in the early post-stroke phase. In clinical research, some types of therapy appear to be more effective than conventional therapy, which often stems from the fact that an experimental group received more therapy [34]. Numerous studies compare different methods of therapeutic interventions. Unfortunately, there are very few investigations that compare different therapeutic doses or the same intensity of diverse therapeutic programmes.
There is an ongoing debate concerning which therapy ought to be applied in stroke patients. There is not enough evidence that would make it possible to choose the best type of UL rehabilitation programme or the one that would ensure optimal intensity and number of exercises. However, new evidence indicates that post-stroke UL physiotherapy is particularly effective if the patient is actively engaged in activity-related arm training [31–33,35]. The most promising strategies of early post-stroke rehabilitation include mCIMT – modified Constraint-Induced Movement Therapy, therapy with the use of robots, Repetitive/Task-Specific Training Techniques, Mental Practice/Motor Imagery and Transcranial Magnetic Stimulation (TMS) [19,29,35,36].
Despite the fact that rehabilitation of stroke patients starts within the first days from stroke onset, the literature of the subject provides little information on UL physiotherapy within the first four weeks after stroke. Existing studies usually refer to small sample sizes or do not meet the criteria of evidencebased practice. Therefore, it is difficult to draw farreaching conclusions on their basis. Currently, attempts are made to adapt modern methods of UL recovery to an early post-stroke stage. The use of CIMT and EMG-NMS in the Dutch multicentre research project EXPLICIT (Explaining Plasticity after stroke) completed in 2013 is a good example. [33]. To the best of our knowledge, until December 2016 there were no Polish studies on UL physiotherapy in the early post-stroke phase and only a few investigations were carried out later on.
Despite increasing evidence (in the last 10 years) showing that it is necessary to increase a therapeutic dose of UL exercises, we can still observe its relatively low and unchanging level particularly in terms of time (in minutes) devoted to therapy in everyday clinical practice [26]. It seems that insufficient UL motor improvement may be brought about by implementing too few exercises. Recovery potential, which is the greatest in the acute phase after stroke, is not adequately used. We only have rudimentary knowledge about the number of activity-related arm repetitions. Drawing on few available reports, an average of 27 repetitions are performed, which is over 15 times less than effective doses observed in animal models (>400 repetitions) [29,30]. Therefore, it can be concluded that such doses are significantly below effectiveness levels. There is evidence that, in the case of patients in the early post-stroke phase, it is possible to apply the same exercise doses as in animal models. Some authors also claim that it is not feasible in clinical practice [4,31]. It seems necessary to create new systemic solutions that would increase a daily therapeutic dose bearing in mind therapeutic safety rules. It is highly likely that UL training intensity in Poland in the early post-stroke rehabilitation phase is insufficient. Basing on the world literature, it can be stated that the most probable causes of limiting therapeutic doses of UL exercises in the early post-stroke phase are as follows: the need to become physically independent as soon as possible, a short stay in a rehabilitation ward, economic constraints (too few physiotherapists and occupational therapists), being unable to move one’s own arm without assistance, a limited access to supplementary devices (e.g. robots or electrical stimulation) as well as the knowledge and habits of the staff [4].
The dose of exercises defined by time has some limitations, i.e. it does not provide any information regarding the actual amount of movement. It is confirmed by the study which revealed that during a 30-minute session in post-stroke inpatient rehabilitation, the number of functional task repetitions ranged from 4 to 369 [37]. The dose defined by the number of task repetitions seems to be more understandable, yet the skill of capturing task repetitions effectively poses a clinical challenge. There is a growing interest in using monitors registering limb movement and accelerometers in order to count activity-related arm repetitions [32]. A low cost of such devices as well as feedback capabilities and the patient’s active involvement in training are the main advantages of using such equipment.
It seems necessary to determine correlations between exercise doses and therapeutic effects, i.e. the level of UL improvement, with the use of rational measurement methods in the early post-stroke phase.
Beside determining a therapeutic dose, an optimal selection of therapeutic means remains unexplained. In the early post-stroke phase, the main goal of UL rehabilitation is to support neurobiological mechanisms of recovery that involve processes of plastic reorganisation of the brain taking into account stroke location and severity. First-choice therapies should include methods oriented at an increased number of repetitions and greater exercise intensity, a patient’s active participation in functional motor tasks and recreating the lost movement while maintaining a natural pattern. We ought to remember that the presence of minimal finger extension predicts full UL functional recovery [7].
There is a lot of evidence that early post-stroke rehabilitation is both necessary and effective; however, there are not enough foundations for determining its optimal intensity and type.
There is a shortage of ample multicentre studies which would be uniform in terms of research groups and tools and which would be aimed at defining an optimal model of functional UL rehabilitation in the early post-stroke phase.
It is disturbing that there are just a few Polish studies regarding this area. A number of the following questions remain unanswered:
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What is the dose of UL exercises in the early post-stroke rehabilitation?
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What therapeutic methods do Polish physiotherapists use?
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Do occupational therapists participate in the early process of rehabilitation?
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How effective is early UL rehabilitation and what are biological limits of improvement?
There is a need to carry out extensive (possibly multicentre) research in order to be able to determine a uniform model of UL physiotherapy and to estimate physiotherapeutic limits of UL improvement.