A newer technology, stacked ABR, may have sensitivity as high as 95% with specificity 88% for smaller tumors. ABR is considerably more cost effective, but MRI provides more information. Stapedius reflex (SR) and caloric vestibular response (CVR) are non-invasive otologic tests for auditory neural function. These are not primary diagnostics for CPA neuromas, and are usually used in conjunction
with ABR. Magnetic resonance imaging
Several different types of magnetic resonance imaging (MRI) may be employed in diagnosis: MRI without contrast, Gd contrast enhanced T1-weighted MRI (GdT1W) or T2-weighted enhanced MRI (T2W or T2*W). Non-contrast enhanced MRI is considerably less expensive than any of the contrast enhanced MRI scans. The gold standard in diagnosis is GdT1W MRI. The reliability of non-contrast enhanced MRI is highly dependent on the sequence of scans, and the experience of the operator. Management
Acoustic neuromas are managed by either surgery, radiation therapy, or observation with regular MRI scanning. With treatment, the likelihood of hearing preservation varies inversely with the size of the tumor; for large tumors, preservation of hearing is rare. Because acoustic neuromas, meningiomas and most other CPA tumors are benign, slow growing or non-growing, and non-invasive, observation is a viable management option. Stereotactic radiosurgery
The objective of irradiation is to halt the growth of the acoustic neuroma tumour, it does not excise it from the body, as the term radiosurgery or gammaknife implies. Radiosurgery is only suitable for small to medium size tumors.
Some studies have found it to be very effective in reducing the duration, severity, and frequency of hemiplegic attacks. It is generally considered the best treatment available, but this drug is thought by some to be of little benefit to AHC patients. Many patients suffer adverse effects without seeing any improvement. Flunarizine also causes problems because it is difficult for patients to obtain, as it is not readily available in the United States. Sodium oxybate
In 2009 through 2011 clinical research at the University of Utah investigated whether sodium oxybate, also known as Gamma-Hydroxybutyric acid is an effective treatment for AHC. Thus far, only a small number of patients have been sampled, and no conclusive results are yet available. While some success has been had thus far with the drug, AHC patients have been known to respond well initially to other drugs, but then the effectiveness will decline over time. Currently, sodium oxybate is used as a narcolepsy-cataplexy treatment, though in the past it has been used controversially in nutritional supplements. This drug was chosen to test because of a possible link between the causes of narcolepsy-cataplexy and AHC. References
External links
Alternating Hemiplegia Information Page at NINDS
Homepage of the Alternating Hemiplegia of Childhood Foundation (AHCF).