Middle cerebral artery syndrome is a condition whereby the blood supply from the middle cerebral artery (MCA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the lateral aspects of frontal, temporal and parietal lobes, the corona radiata, globus pallidus, caudate and putamen. The MCA is the most common site for the occurrence of ischemic stroke.

Depending upon the location and severity of the occlusion, signs and symptoms may vary within the population affected with MCA syndrome. More distal blockages tend to produce milder deficits due to more extensive branching of the artery and less ischemic response. In contrast, the most proximal occlusions result in widespread effects that can lead to significant cerebral edema, increased intracranial pressure, loss of consciousness and could even be fatal. In such occasions, mannitol (osmotic diuretic) or hypertonic saline are given to draw fluid out of the edematous cerebrum to minimise secondary injury. Hypertonic saline is better than mannitol, as mannitol being a diuretic will decrease the mean arterial pressure and since cerebral perfusion is mean arterial pressure minus intracranial pressure, mannitol will also cause a decrease in cerebral perfusion.

Contralateral hemiparesis and hemisensory loss of the face, upper and lower extremities is the most common presentation of MCA syndrome. Lower extremity function is more spared than that of the faciobrachial region. The majority of the primary motor and somatosensory cortices are supplied by the MCA and the cortical homunculus can, therefore, be used to localize the defects more precisely. Middle cerebral artery lesions mostly affect the dominant hemisphere i.e. the left cerebral hemisphere.

Meditation-relaxation (MR) therapy is a published direct treatment for sleep paralysis. The treatment was partly derived from the neuroscientific hypothesis suggesting that attempting movement during sleep paralysis (e.g., due to panic-like reactions) can lead to neurological distortions of one's "body image", possibly triggering hallucinations of shadowy human-like figures. The therapy is based on four steps applied during sleep paralysis: (1) reappraisal of the meaning of the attack (cognitive reappraisal); which entails closing one's eyes, avoid panicking and re-appraising the meaning of the attack as benign. (2) psychological and emotional distancing (emotion regulation); the sleeper reminds him- or herself that catastrophizing the event (i.e., fear and worry) will worsen and possibly prolong it; (3) inward focused-attention meditation; focusing attention inward on an emotionally salient positive object; 4) muscle relaxation; relaxing one's muscles, avoid controlling breathing and avoid attempting to move.There are preliminary case reports supporting this treatment, although no randomized clinical trials yet to show its effectiveness.

Note: *faciobrachial deficits greater than that of the lower limb

Though no large trials have taken place which focus on the treatment of sleep paralysis, several drugs have promise in case studies. Two trials of GHB for people with narcolepsy demonstrated reductions in sleep paralysis episodes.