I. Introduction
Stroke is an acute onset of neurological dysfunction due to an abnormality in cerebral circulation with resultant signs and symptoms that corresponds to involvement of focal areas of the brain. WHO (1989) classified stroke as neurological deficit which must persist for at least 24 hour duration.Stroke is the most common life threatening neurological disease and is main cause of long term disability in adults worldwide. [1-2] Stroke is major health problem in India. The prevalence of stroke in India was estimated as 203 per 100,000 population above 20 years, amounting to a total of about 1 million cases. [3]
The effects of stroke are variable depending on location of the lesion as well as the size. The most typical symptom of stroke is hemiparesis or hemiplegia, which ranges from weakness to full paralysis of the body opposite to the side of the supratentorial lesion. [4]In addition to limb muscles trunk musculature is also impaired in stroke patients. Contrary to limb muscles in hemiplegia in which motor paralysis affects one side of the body the trunk muscles are impaired on both ipsilateral and contralateral side of body to that of lesion. Trunk muscles play an important role in the support of our bodies in antigravity postures such as sitting, standing and in the stabilization of proximal body parts during voluntary limb movements. [5] Good trunk stability is essential for balance and extremity use during daily functional activities. Several studies have identified deficits of trunk muscle strength and poor trunk control in stroke patients. [6] Poor recovery of trunk muscle performance results in a severe disability and a reduction in the activities of daily living. In stroke rehabilitation, trunk muscle performance is an important factor in predicting the functional outcome. [7]
In addition to limb and trunk impairments hemiplegic stroke patients frequently present balance abnormalities in relation to trunk impairment and are associated with poor balance and falls. [8]It has been demonstrated that stroke patients have abnormal and delayed postural responses in the lower extremity muscles in standing. Other postural control problems after stroke are loss of anticipatory activation of trunk muscles during voluntary movements, an increase in sway during quiet standing, a decreased area of stability in stance, delayed and disrupted equilibrium reactions, and reduced weight bearing on the paretic limb and increased risk of falling. [9]