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Introduction
The cerebellum occupies most of the posterior brain and, more specifically, the posterior cranial fossa [1]. The functional role of the cerebellum is quite important in humans as it is responsible for posture control and body balance, muscle tone, eye movement, motor planning, motor control, as well as motor learning [1]. The cerebellar vasculature consists of three main arteries, the superior cerebellar artery (SCA), the anterior inferior cerebellar artery (AICA), and the posterior inferior cerebellar artery (PICA) [2].
Cerebellar infarction is to ischemic or hemorrhagic type episode affecting the posterior cranial fossa region and in particular, the cerebellum [3]. In the US, 800,000 vascular strokes are recorded every year where 87% belong to the ischemic stroke category [4]. More specifically, cerebellar infarcts account for 2-3% of all strokes. The gender ratio of cerebellar infarction is 2/3 for men, with an average age of 65 years. The mortality rate is reaching 23%, but in recent years this rate has decreased dramatically due to the evolution of healthcare with magnetic resonance imaging and computed tomography making a significant contribution to the early management of such an episode [3, 5].
Cerebellar infarction can be caused by arterial occlusion, mechanical compression, or vasoconstriction. The source of blockage can be created either through the circulation of the heart, called the thromboembolic phenomenon, or through the cerebellar vessel itself, known as the thrombotic effect, due to various vascular diseases and atherosclerosis [3].
There are many factors that can contribute to the formation of a cerebellar infarct with the most common causes being atherosclerosis, atrial fibrillation, paradoxical embolism, cardiomyopathy, and heart failure [3, 5]. 
In the first hours that the patient experiences the infarct, he or she will experience severe headache, vomiting, sleepiness, and changes in psychology [3]. Depending on the damaged artery, there will be different symptomatology. Τhus, damage to the PICA, which is the most common, involves the development of two possible syndromes, Wallenberg syndrome, or Horner syndrome [1]. Some of the symptoms are ataxia, nystagmus, vertigo, myesis, and loss of sensation in line with and opposite side of the lesion [5].
For infarction in the SCA, the symptoms are more severe due to the greater distribution of the artery in the cerebellum [5]. Indicatively, severe ataxia in limbs and gait, dysarthria, dysmetria, paresis, loss of sensation of the opposite side of the body, and visual-motor nystagmus are observed [3].
Finally, common symptoms of AICA strokes as the rarest posterior circulation strokes are vertigo, nystagmus, falling to the side of the lesion, associated tinnitus and deafness, dysarthria, and dysphagia [1].
For the assessment of a patient with a cerebellar infarct, the head impulse test, Nystagmus, test of skew exam (HINTS) is mainly used as a preliminary and rapid screening tool for the diagnosis of central (cerebellar infarction) or peripheral (vestibular neuritis) vertigo. It is performed in patients with continuous, for hours or days, symptoms of vertigo and sudden nystagmus and consists of the head impulse test, the nystagmus test, and the skew test [3]. 
Several assessment scales can be used to evaluate the severity of symptoms in these patients, with interest focusing on two ataxia assessment scales. Firstly, the scale for the assessment and rating of Ataxia (SARA) through eight different parts assessing gait, posture, sitting, speech disorders, the index finger–index test, the index finger–nose test, the fast palm alternation test (pronation–supination), and the heel–shin test [6]. It is worth mentioning that the SARA has been found to have a very good correlation with the patient’s gait and independence level in the activities of daily living (ADL) [7]. Finally, the international cooperative ataxia rating scale (ICARS) assesses the patient through four subscales of postural and gait disorders, limb ataxia, speech disorders, and oculomotor disorders [8].
The treatment of these patients is mainly focused on surgery and drug therapy. Some of the most common surgical operations used are decompressive hemicraniectomy, sub-occipital craniectomy, extraventricular drainage, and ventriculostomy [3, 5, 9]. Regarding pharmacological treatment, the most commonly used drugs are aspirin, clopidogrel, atorvastatin, mannitol, and heparin [9-12]. Also, since this is a neurovascular episode, the contribution of the rehabilitation team in general, and physiotherapy in particular, is extremely important, always aiming at the functional independence of the patient. Using individualized physical therapy programs, appropriate exercises, as well as appropriate equipment that only a qualified physical therapist knows how to use, it is possible to improve the performance of patients with cerebellar infarction, as shown by other cerebrovascular diseases, such as stroke [13]. In addition, similar research has been conducted on the effectiveness of physiotherapy and therapeutic exercise programs in cerebellar dysfunction and cerebellar ataxia, showing very good results for disease severity and balance, always suggesting further study in this field [14, 15]. This overview of existing studies aimed to investigate the effectiveness of physiotherapy programs on the symptoms of patients with cerebellar infarction.

Materials and Methods
A literature search was performed using PubMed (MEDLINE), Scopus (Elsevier), CENTRAL (cochrane central register of controlled trials), Web of Science, SPORTDiscus (EBSCO), and ResearchGate databases on September 4, 2022. An additional search of PubMed Central and Google Scholar databases was performed on September 8, 2022. To conduct the review, the databases were searched using defined keywords and certain eligibility criteria. The following keywords were used for the search: physiotherapy, physical therapy, rehabilitation, therapeutic exercise, exercise, cerebellar infarct, cerebellar infarction, and cerebellar blockage. The search strategies in the databases are given in Table 1.


The inclusion criteria were: a) Randomized, pilot or case studies, b) Studies published exclusively in the English language, c) The age of the subjects being over 18 years, d) Studying subjects diagnosed with cerebellar infarction, e) Physiotherapy, therapeutic exercise, rehabilitation, or exercise in general as an intervention, and f) Evaluation of any parameter that may be affected as a symptom in this group of patients and evaluated with the relevant evaluation tool. In contrast, the exclusion criterion was studies that followed vestibular or cognitive rehabilitation as the type of intervention.
The eligibility of studies was assessed by two separate reviewers and there was the possibility of a third-party consensus in case of disagreement, which was only needed in a study where the main reviewers were not confident enough about its inclusion in the qualitative synthesis of the overview [16]. 

Results 
The number of initial records searching the six main databases was 155. After removing the duplicate studies, 97 cases remained, and after removing the articles by title, six studies remained to read their abstracts. It should be mentioned that Microsoft Excel was used to remove duplicate studies by deleting duplicate variables, but the reviewers also manually deleted duplicate studies. After reading the abstracts, five studies were removed and finally, only one study met the criteria. In addition, a second search of two databases was performed, in which the records screened were 1322. After reading the titles of the studies, the abstract, and the full text of some of them, we concluded that five studies met the inclusion criteria of this overview. Thus, the total number of articles included in the overview was six. The process of selecting studies was also presented graphically based on the PRISMA 2020 (preferred reporting items for systematic reviews and meta-analyses) flowchart in Figure 1 [17].  Of the 1477 initial records, only six studies met the entry criteria, of which two cases were research studies with more than one participant and the remaining four were case studies. Of the included studies, two cases were conducted in the United Kingdom and one study each was conducted in Japan, Germany, Egypt, and the US. Also, the total sample of participants in these studies was 38, with the majority of them being female. The interventions of the studies involved a program of balance and active exercises for the trunk, hips, and knees with emphasis on extensors, a treadmill exercise program, a task-oriented approach, a metronome-based walking program, a program based on general physiotherapy principles and tools from the intensive care unit (ICU) to outpatient, and finally, a program based on virtual reality. The duration of interventions ranged from two to 57 weeks, and the assessment tools used in the studies were varying, assessing ataxia, gait, balance, function, etc.
Details of the sample, design, intervention, evaluation, and effectiveness of each study are presented in Tables 2 and 3.






It should be noted that in two research studies, the sample was divided into groups based on a randomization method. In addition, in these two studies, one did not correctly report the number of participants by gender compared to their sample size, as well as information on infarct location, and the second study did not report the characteristics of the participants who finally carried out the intervention. Thus, in Table 2. the sample characteristics described are approximate for these two studies [18, 19].
According to the results of the analyzed studies, a program of balance and active exercises on the trunk, hips, and knees with emphasis on the extensors showed that it helped the static balance of the participants who followed the program, as opposed to the dynamic balance of those who only did a balance exercise program, which showed no difference in effectiveness compared to the group who also did extensor exercises. In contrast, a treadmill exercise program showed no differences between groups in ataxia symptoms, with one group receiving an intervention and the other not. 
Regarding the case studies, the effect of the task-oriented approach showed an improvement in both the gait and functional independence of the patient in a relatively short period (4-5 weeks). Improvement in gait parameters was also found in the study using the metronome, although no safe long-term conclusions can be drawn due to the very short duration of the intervention. Furthermore, a well-structured physiotherapy program based on general physiotherapy principles and tools, from the ICU to outpatient, with a duration of 57 weeks, was found to have very good results for the patient’s full independence in ADLs. Finally, a virtual reality program based on balance and weight shifting showed beneficial effects on the patient’s ataxia symptoms, balance, and return to work (Table 3).

Discussion
This overview of the available studies is the only one that exists in this field and considers it necessary for the clinical and scientific field of physiotherapists in the management of such cases. With no time limit for finding literature and including any type of study from eight databases, the research gaps for the management of patients with cerebellar infarction emerge, and as can be seen, there are no similar studies to compare with those mentioned above, as all those that were relevant to the selected topic. 
As it seems from the research studies where the sample size was larger, a personalized program of balance and strengthening exercises of the body’s extensor muscles is very helpful in stabilizing the patient’s body to cope with daily functional demands and probably creating the patient’s security and confidence to perform activities that require balance. Perhaps the treadmill exercise program was not as successful, even though it targeted the patient’s functional gait, due to the patient’s failure to be demarcated into specific rehabilitation frameworks based on symptoms. Also, the task-oriented approach program that was used in a case study showed very positive results for gait and balance in stroke patients [23]. Overall, in combination with the case studies, gait and balance exercise programs improve a patient’s functionality, thereby achieving his/her independence in ADLs and reducing his/her symptoms. Finally, the results of this overview are in line with the findings of systematic reviews and meta-analyses that studied cerebellar ataxia and cerebellar dysfunction as they found the positive response of physiotherapy and therapeutic exercise programs mainly on the balance of these patients [14, 15]. 
The outcome of patients after cerebellar infarction is that they will have better hand mobility and walking ability in the ADLs than patients with cerebral stroke [24]. The process of the patient’s recovery and the outcome depend on the severity of the damage and the initial functional level. There is an improvement in the mean functional independence measure (FIM) scale score after recovery from infarction, but the patient’s pre-existing comorbidities and functional status at the time of discharge from acute hospitalization are also important [25]. Finally, in the study using functional magnetic resonance imaging (fMRI), recovery after infarction was based on cerebellar reorganization on the infarct side and activation of cerebellocortical loop connections with ipsilateral cerebrum and contralateral cerebellum movement control [26]. 

Conclusion
It seems that the physical therapy approach of the patient with cerebellar infarction is focused on a program of balance exercises and walking exercises, which always aims at the functional independence of the patient. Individual research in this field is extremely necessary in order to provide properly structured and clinically proven forms of physiotherapy intervention for these patients. 
This overview of existing studies is an incentive to conduct more studies on cerebellar infarction, especially studies with a larger number of participants or even randomized controlled trials with a control group for safer, valid, and reliable conclusions. Also, future research can target the selection of interventions for patients with infarct in a specific cerebellar artery, giving appropriate conclusions for the respective symptomatology. In addition, it is considered important to emphasize the long-term outcomes of the studies, since only a few discussed studies had long durations of both intervention and follow-up. 
Regarding the limitations of the present overview, initially, due to the variety of intervention programs, no safe conclusion can be drawn about the most effective form of intervention in general for the symptoms of patients with cerebral infarction. Furthermore, safe conclusions cannot come up due to not assessing the quality of the included studies. Also, the long-term effects of each intervention cannot be known as very few studies have re-evaluated their sample. Finally, the conclusions do not address treatment guidelines for patients with infarction in a specific cerebellar artery but provide general guidance.

Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be considered in this research.

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors.

Authors' contributions
All authors equally contributed to preparing this article. 

Conflict of interest
The authors declared no conflicts of interests.

Acknowledgments
The authors would like to thank Besios Thomas for helpful comments and discussion and everyone else who took part in this review article. 


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