Alternating hemiplegia (also known as crossed hemiplegia) is a form of hemiplegia that has an ipsilateral cranial nerve palsies and contralateral hemiplegia or hemiparesis of extremities of the body. The disorder is characterized by recurrent episodes of paralysis on one side of the body. There are multiple forms of alternating hemiplegia, Webers syndrome, middle alternating hemiplegia, and inferior alternating hemiplegia. This type of syndrome can result from a unilateral lesion in the brainstem affecting both upper motor neurons and lower motor neurons. The muscles that would receive signals from these damaged upper motor neurons result in spastic paralysis. With a lesion in the brainstem, this affects the majority of limb and trunk muscles on the contralateral side due to the upper motor neurons decussation after the brainstem. The cranial nerves and cranial nerve nuclei are also located in the brainstem making them susceptible to damage from a brainstem lesion. Cranial nerves III (Oculomotor), VI (Abducens), and XII (Hypoglossal) are most often associated with this syndrome given their close proximity with the pyramidal tract, the location which upper motor neurons are in on their way to the spinal cord. Damages to these structures produce the ipsilateral presentation of paralysis or palsy due to the lack of cranial nerve decussation (aside from the trochlear nerve) before innervating their target muscles. The paralysis may be brief or it may last for several days, many times the episodes will resolve after sleep.
The initial diagnosis is made based on the presence of neurologic and ophthalmic disease but the disease progresses differently in each patient so after initial diagnosis the patient should be monitored frequently in order to handle further complications resulting from the syndrome. Treatment
Medical treatment of hemiplegia can be separate into several different categories:: 779 
prophylactic treatment by avoiding triggers and long-term drug treatment
acute management of the episodes
management of the epilepsy
sleep as a management technique.Seizure trigger include exposure to cold, emotional stress, fatigue, bathing, hyperthermia/hypothermia, and upper respiratory infection. A drug called flunarizine, which is a calcium channel blocker can help to reduce the severity and the length of attacks of the paralysis. Flunarizine
Many children affected by alternating hemiplegia also have epilepsy. Seizures may occur during an attack but more often occur between attacks. Anti-epilepsy drugs are given to prevent or lessen the seizures, but the drugs often dont work and have severe side effects that require the patient to discontinue use. Flunarizine, which blocks calcium channels, is an antiepilepsy drugs used in 50% of patients, and has been shown to shorten the duration of attacks as well as reducing the severity of the attacks. While Flunarizine does not stop the attacks, it is most common drug prescribed to treat those with alternating hemiplegia. : 779

Sleep and diet
Sleep is also used as a management technique. An early indication of an episode is tiredness so medication such as melatonin or Buccal midazolam can be administered to induce sleep and avoid the episode.