**2. Right versus left hemisphere stroke**

Right hemisphere function is to control not only the movement of the left side of the body, but also analyze spatial orientation (distance, depth, position, size, and stereotaxis) and

Stroke Rehabilitation 23

In summary, hemorrhagic stroke has higher mortality rate than non-hemorrhagic in acute phase and often requires emergent surgical intervention for survival. However, hemorrhagic stroke survivors without significant surgical complications make better functional

Severity and types of impairments resulted from a stroke depend on stroke site and lesion size. Most common impairments are 1) motor dysfunction (paralysis of extremity, face, and oropharyngeal muscles), 2) sensory dysfunction (decreased sensation, perception disorder, abnormal sensation), 3) sphincter dysfunction (bowel and bladder incontinence), 4) cognitive dysfunction (anomia, aphasia, dementia), 5) emotional disturbance (depression, apathy).

1. Paralysis of one side of body (hemiplegia): It develops in very early phase of stroke. If stroke lesion is in the right hemisphere, paralysis develops in the left face and the extremity. But stroke lesion located in the right brainstem, develops paralysis in the right face and left extremity. Most patients with stroke complain of flaccid extremity as an initial symptom. The flaccid extremity usually evolves to spastic extremity as part of its natural course. Details of motor function recovery will be described in the follow

One side of bulbar muscle paralysis results in oropharyngeal dysfunction (dysphagia). Stroke patient with dysphagia needs non-oral feeding until safe swallowing recovered. Depending on the severity of dysphagia, stroke patient needs nasogastric or gastrostomy/jejunostomy tube feeding. VFSS (videofluorographic swallowing study), also called videofluorographic modified barium swallowing study, is a standard diagnostic test to evaluate swallowing function. Penetration is defined when a bolus moves aberrantly down to the vestibule above the true vocal fold. This may trigger a coughing or a choking reflex after swallowing the bolus. Aspiration occurs when a bolus passes farther down through the true vocal folds and enter into the trachea and lungs. Most of patients with dysphagia return to a regular diet in early post-stroke phase25, 26. Compared to other lesions, dysphagia develops more common and less favorable outcome in brainstem stroke, however 88% returned to regular oral intake 4 months after stroke27. Tracheostomy increases the risk of aspiration because of the limitation of laryngeal elevation during swallowing. Selection of adequate texture of meals and meticulous monitoring of swallowing are critical to prevent aspiration. 2. Sensory impairment: stroke patients have sensory impairment of peripheral and/or central sensation. Peripheral sensory impairments include hypesthesia/paresthesia, loss of proprioception and position, or loss of pain/temperature. Agraphesthesia and astreognosis is seen in central sensory impairment. Those impairments cause stroke patients to needs more assistance for learning motor and cognitive skills. Reception is the processing of registration of sensations or stimuli which are collected through sensory organs (nose, eye, ear, skin, tongue, joint, or internal organs). Received sensations or stimuli are conveyed to the corresponding primary sensory cortexes. For example, visual sensation reaches occipital cortex via optic pathways. Perception is the next process to interpret the received sensations or stimuli. Perception is higher cortical function than reception and many parts of brain are involved. Details of perception

disorder will be discussed in the following perception disorder.

improvement in early phase of rehabilitation than those with non-hemorrhagic stroke.

**4. Impairments and disabilities sequelae to stroke** 

section (Motor function recovery).

perceptual abilities. Stroke patients with right hemisphere lesion often demonstrate lack of safety awareness and impulsive behaviors. With these complex impairments, they have difficulties in re-learning ADL (activities of daily living). For example, they are unable to read or copy letters, forget to clean their left side body, or ignore to wear assistive devices for activity. Even though they can maintain speech-language function better than patients with left hemisphere stroke patients, they may make errors in grammar.

Major functions of the left hemisphere are to control the movements of the right side of the body and to maintain speech-language function. Patients with left hemispheric strokes sustain right hemiplegia and aphasia. They behave cautiously and need more time to complete the same task compared with right hemispheric stroke patients. Different types of aphasia can occur depending on the specific site of the lesion in the left hemisphere.

It is controversial whether rehabilitation outcomes differ depending on which hemisphere the lesion is occurs6-8. Possible reasons for the controversy are different outcome scales, measurement domain, presence of hemi-neglect, and evaluation timing. For example, if the outcome compared is vocational rehabilitation, patients with right hemisphere lesion show better outcome9. The higher percentage of patients returning to work with a right hemispheric lesion largely can be explained by preserved speech-language function. However patients with right hemispheric lesions more frequently develop social defects than those with left hemispheric lesions10. In contrast, if regaining arm function is measured as a rehabilitation outcome, poorer outcome is reported in right hemispheric lesions11.

Hemi-neglect develops more commonly in stroke patients who have right hemispheric lesion compared to the left. There is a wide range of incidence reported, because of different evaluation tools and evaluation timing12,13. Among patients with right hemispheric lesions, patients with hemi-neglect are more disabled and stay longer at rehabilitation facilities than those without hemi-neglect14. Again, one possible reason of controversy in outcomes of patients with stroke between right and left hemispheric lesions is that patients with a concurrent right hemispheric lesion with hemi-neglect has more disability than would be with a right hemispheric lesion alone15. Future studies excluding hemi-neglect patients may help clarify the difference in disability between right and left hemiplegia patients16.
