Also, synchronous afferent stimulation of peripheral muscles induces organizational changes in motor representations, characterized both by an increase in map size of stimulated muscles and a reduction in map separation, as assessed using transcranial magnetic stimulation.The cross-connectivity between areas that are normally segregated in the sensory cortex may prevent normal sensorimotor feedback and so contribute to the observed co-contraction of antagonist muscle groups, and inappropriately timed and sequenced movements that underlie the symptoms of focal dystonia. It is hypothesized that a deficit in inhibition caused by a genetically mediated loss of inhibitory interneurons may be the underlying cause of the deficits observed in dystonia.While usually painless, in some instances the sustained contraction and abnormal posturing in dystonia cause pain. Focal dystonia most typically affects people who rely on fine motor skills—musicians, writers, surgeons, etc. It is thought that the excessive motor training those skills require may contribute to the development of dystonia as their cortical maps become enlarged and begin to overlap. Focal dystonia is generally "task-specific," meaning that it is only problematic during certain activities. Diagnosis
The diagnosis of focal dystonia is highly dependent on the history of the patient, as physical exam is typically normal, and ruling out other causes of movement disorder. The main types of are blepharospasm, oromandibular dystonia, spasmodic dysphonia, spasmodic torticollis, and limb dystonia, all affecting a different region of the body. Labs and imaging may be ordered as workup to evaluate for other causes of dystonia.
The drug is thought to increase blood flow to the inner ear and to prevent the frequency and intensity of episodes. While Betahistine is considered safe, there is insufficient evidence that it is an effective treatment. It is not FDA approved in the United States, yet has still been clinically observed to benefit patients, and is considered safer and more effective than diuretics. Betahistine at high doses (such as 144 mg/day) can yield similar vertigo control as intratympanic dexamethasone.Antivirals have been proven effective for those who suspect a viral cause for their cochlear Hydrops.For some, surgery may be effective, such as an endolymphatic sac decompression. Surgery is often reserved for cases where other measures have proven ineffective and/or when vestibular issues are the main complaint, as it runs the risk of causing hearing or other nerve damage. Prognosis
The symptoms of cochlear hydrops fluctuate, and the condition tends to stabilize or go away on its own after several years. However, because the organ of Corti undergoes stress during the hydrops episodes, long-term hearing loss, tinnitus, or hyperacusis is possible. It is considered by some that cochlear hydrops is an early form of Menieres disease. However, while all people with Menieres disease have some form of hydrops, the majority of cochlear hydrops patients do not go on to develop Menieres disease. It takes an average of one year from the onset of symptoms for someone to develop full Menieres disease, if at all.