Stroke is a leading cause of death and long-term serious disability [1]. 80% of all patients with stroke experience hemiparesis of contralateral limbs. Spontaneous recovery is less likely to occur six months following a stroke [2]. Muscle weakness and impaired motor control due to hemiparesis lead to functional impairment and poor quality of life.

Hyperbaric Oxygen Therapy (HBOT) is a treatment in which a patient breathes 100 % oxygen while inside a treatment chamber at a pressure higher than the sea level pressure. Scientific evidence strongly suggests its use as a main treatment modality in arterial gas embolism, decompression sickness, and severe carbon monoxide poisoning [3].

HBOT was also administered in cases of acute ischemic stroke and poststroke patients and the emerging literature on the subject reported that some patients may benefit from HBOT and others may not [4]. Significant improvement has been seen in motor and all cognitive domains after administering HBOT to a stroke patient even in the chronic stage. HBOT-induced neuroplasticity is mediated by neurogenesis of endogenous neural stem cells, stimulating cell proliferation, improved maturation and myelination of injured neural fibers, regeneration of axonal white matter, and stimulation of axonal growth, thus increasing the ability of neurons to function and communicate with each other [5]. This pilot study aims to establish more information about hyperbaric oxygen therapy for this group of patients, so that a valid treatment protocol can be set to initiate the best possible comparative study.This randomized, double-blind, Pilot study will be conducted on 30 patients after approval by the institutional ethical committee. All patients will be randomly allocated into two groups of 15 each. A computer-generated random number table will do randomization.

Group H: 15 patients will receive Hyperbaric oxygen therapy along with conventional physiotherapy

Group C: 15 patients will receive conventional physiotherapy alone

All patients will be taught about hyperbaric oxygen therapy and their related risks if any. All patients will also be taught about the measurement variables and their outcomes. After getting written informed consent, all patients will be invited for baseline evaluations of demographic characteristics such as age, gender, BMI, vitals (pulse rate, systolic blood pressure, diastolic blood pressure, and SPO2), the onset of stroke (duration), neurological deficit, affected side and associated comorbidities like Diabetes mellites, hypertension, thyroid dysfunction, etc. 15 patients of group H, who survived a stroke episode with hemiparesis 3 to 6 months before inclusion, will receive 24 sessions of hyperbaric oxygen therapy along with conventional physiotherapy.

The following HBOT protocol of 24 sessions will be practiced:

2.0 ATA 100% oxygen for 60 mins, 4 days a week for 6 consecutive weeks.

Patients of group C will also spend equal time as group H in a hyperbaric chamber, but on 1 ATA air for proper blinding purposes. Both patients and neurologists will be unaware of group allocation and treatment advised.

All patients will be assessed for neurological functions such as motor function, cognitive function, and quality of life two times, before the start of therapy as a baseline evaluation (T1), after completion of 24 sessions of HBOT (T2) by using NIHSS, MMSE and short-form health survey with 36 questionnaires respectively by a neurologist.

All patients of group H will undergo an ENT checkup before therapy to rule out eustachian tube dysfunction and any middle ear pathology. All patients of Group H will undergo an ophthalmology checkup after each week during the therapy phase. All patients will be allowed to take treatment for their comorbid conditions like hypertension, dyslipidemia, hypothyroidism, and cardiac disease under the supervision of a neurologist. All other treatment measures will be allowed during the study period.

The outcome variables will be NIHSS, MMSE, and QOL.