2.3. Interventional Methods

The hippotherapy exercises will consist of four phases performed sequentially:

The hippotherapy protocol is substantially the same for every patient knowing that a reinforcement of postural balance, symmetry, hip and shoulder dissociation, spinal joint mobility, and muscle tone regularization are needed in both Rankin 3 and 4 patients. These will be obtained through the horse movement at a walk and the simulator movement. During hippotherapy, the postural balance work and the muscle tone regularization are background tasks [11,12]. The physiotherapist will simultaneously work the upper limb through repetitive task-specific training, muscle strength training, bilateral training, and mental practice. The intensity of the exercises will be fully tailored and will depend on the patient’s clinical heterogeneity, fatigability, and confounding factors.

Standing and walking is not mandatory for mounting a horse during hippotherapy. The institute is equipped with a ramp, which allows for the wheelchair to be positioned alongside the horse. Our trained staff operate the transfers of non-walking patients. Once on the horse, the patient is usually able to maintain an adequate postural balance. The therapist walking alongside the horse during the session is an occasional form of support when needed. The horse is equipped with a specially manufactured leather pad with handles (no saddle, no stirrups), allowing for the patient’s maximum freedom of movement and contact with the horse’s back.

During the remaining 18 weeks, the treatment options for each patient will include physiotherapy (motor training and functional training), occupational therapy, language therapy, and psychological and social support in the CHSF (see Section 2.3.2 below).

Patients of the control group will follow a standard outpatient rehabilitation treatment during 22 weeks, consisting of a combination of five half-day physiotherapy, occupational therapy, speech therapy and psychotherapy sessions per week according to the patient’s needs. For the patients with a modified ranking scale comprised between 3 and 4, it is likely that the work targeted on gait, balance, and mobility will focus on gait-oriented physical fitness training, repetitive task training, muscle strength training, and the treadmill training when possible. People with difficulty using their upper limb should be given the opportunity to undertake as much tailored practice of upper limb activity as possible. Interventions, which can be used routinely, involve constraint-induced movement therapy in selected people, repetitive task-specific training, and mechanical-assisted training. One or more of the following interventions can be used in addition to the ones above: mental practice, electrical stimulation, biofeedback in conjunction with conventional therapy, bilateral training, and mirror therapy. Moreover, special attention will be paid to manage mild to moderate spasticity through early comprehensive rehabilitation. Additionally, contractures must be carefully monitored and prevented by conventional motion therapy. Particularly common is the loss of shoulder external rotation, elbow extension, forearm supination, wrist and finger extensions, ankle dorsiflexion, and hip internal rotation. People with severe weakness tend to develop contractures. Any joint or muscle not regularly used can be subject to soft tissue complications, which will eventually limit movement and may cause pain.

As several techniques are likely to be used, a record of the number of rehabilitation sessions (physiotherapy, occupational therapy, speech therapy, and psychotherapy) and their type will be collected for each patient during the study period and used as a covariate.

It is difficult to determine the minimum effective quantity of the required neurological rehabilitation. Scientific evidence is lacking and studies have biases of several kinds. To date, the effectiveness of many rehabilitation techniques has not been systematically demonstrated. According to a 2014 review of the literature [50], the studies carried out are highly heterogeneous (e.g., type of rehabilitation, included patients, quality of structures, and type of evaluation) and have a low methodological quality [50,51,52]. The overall effectiveness of stroke rehabilitation has been substantiated from older studies generally mainly showing reductions in mortality, dependency rates, and risk of institutionalization.

On the one hand, in this rather empirical context, sessions of at least 45 min by type of rehabilitation are commonly recommended (more if the patient can bear it). It is accepted that the frequency is daily or at least 5 days a week. Rehabilitation should be conducted for at least 8 weeks “as long as improvement continues”. During the first two weeks, frequent, short sessions of progressive intensity are preferred. The intensity with which rehabilitation is conducted varies depending on dispensing structures. Thus, rehabilitation in a specialized service with full hospitalization or day hospitalization offers possibilities to perform intensive multiple rehabilitation, which is more difficult to perform with independent professionals [50].

On the other hand, a hippotherapy session lasts one hour per day during which between 3000 and 4500 contractions of each postural muscle are sequentially realized in a background mode (horse at a walk) in parallel to other requests (fine motor skills, cognitive elaboration, and psychic work), well beyond what a conventional rehabilitation session allows. Given the intensity of each session that mobilizes the individual in his/her entirety (e.g., somatic, sensory, cognitive, emotional and motivational, and psychic spheres), and relying on our clinical experience over the last decade, we unequivocally respect a certain rhythm by integrating the duration of the patient’s processing of physical/mental skills and the ensuing fatigue. Additionally, thanks to the enriched environment brought by hippotherapy, we notice continuous functional improvements, even beyond the theoretical period of consolidation of the neurological outcome after injury [53,54]. Overall, the strong stimulation of the sensory, sensitive, and motor spheres promotes and interacts with the mechanisms related to the tasks’ performances in the cognitive and emotional domains through the activation of multiple neural networks [35,55]. The degree of change associated with neuroplasticity through hippotherapy is most likely linked to both the relevance of the activity and the intensity and frequency of the elements that constitute it [56,57,58]. A systematic validation is carried out at the Equiphoria Institute to provide a solid theoretical foundation for this approach.

At each evaluation, the investigator will determine whether any adverse events or serious adverse events (AEs or SAEs) occurred. All adverse events occurring during the study will be recorded on the appropriate case report form (eCRF) page by the investigator. The nature, severity, and relation of the adverse event to the study protocol and treatment will be documented. A safety plan has been duly integrated in the Trial Master File.