Effectiveness of Intensively Applied Mirror Therapy on Older Adults With Post-stroke Hemiplegia: a Preliminary Trial.

INTRODUCTION:

Cerebral ischemia or intracranial haemorrhage are the main characteristics of cerebrovascular diseases like the stroke. The disruption of the functional neuronal integrity after a stroke can affect both motor and cognitive states. The most characteristic motor sequel of a stroke is hemiplegia, characterized by the loss of voluntary movement, muscle tone, and osteotendinous reflexes from the affected hemiparetic body.

Mirror therapy (MT) was born in the late 1990s and was initially used to treat "phantom limb" symptoms. More recently, the effectiveness of this therapy in motor rehabilitation on post-stroke hemiparetic limbs has been also described. Due to its low cost and simplicity, it has become one of the most widely used therapies. The purpose of the MT is to perform bilateral and synchronous movements with the non-paretic limb, creating an illusion of movement in the brain.

The effectiveness of MT on brain injury can be explained in three ways. First, mirror neurons can recognize an action and activate motor learning through imitation. Secondly, neurological damage from a stroke usually causes inflammation and oedema that interrupts the transmission of motor information. The illusion of movement created MT reawakens these motor pathways by reactivating them. Finally, after suffering a stroke, patients have a different degree of activity in their cerebral hemispheres, being much lower in the injured hemisphere. The performance of MT contributes to reducing this imbalance.

The MT is based on visual and somatosensory information that is processed in the central nervous system. The movements of the non-paretic limb reflected in the mirror create an illusion of normal movement of the affected limb. This neurophysiological phenomenon stimulates the same cortical areas that are active during movement observation (somatosensory cortex, premotor and primary motor cortex, supplementary motor area, cerebellum and basal ganglia). The mirror reflection leads to additional activation of the contralateral hemisphere to the perceived limb, producing an increase in the hemiparetic cortico-muscular excitability. However, despite its valuable role on patients with post-stroke hemiplegia, its effectiveness in older subjects has not been defined so clearly.