He suggested that the committee ask Dr. Gibson to submit a technical guideline on the technique so that it could be performed in a standardized way.
Explore This IssueNovember 2013
Tsutomu Nakashima, MD, PhD, professor of otorhinolaryngology at Nagoya University Graduate School of Medicine in Nagoya, Japan, shared his findings on the imaging of endolymphatic hydrops (EH). The approach involves the injection of gadolinium, either intratympanically or intravenously. With intratympanic injection, imaging can be done after a 24-hour waiting period. With intravenous, the waiting period is four hours.
In a study conducted by Dr. Nakashima’s group, 25 ears were evaluated in patients with acute low-tone sensorineural hearing loss. Cochlear EH was found in 23 ears (92 percent), and vestibular EH was found in 22 ears (Otol Neurotol. 2013;34:1241-1246).
Dr. Nakashima said that there are many cases of asymptomatic EH, and that the asymptomatic form that precedes Meniere’s disease can be found more frequently using MRI than other techniques.
Dr. Hornibrook made a few cautionary remarks, though. He said that there’s a hope that MRI images will be the gold standard eventually, but “the problem is that there is variable penetration of gadolinium into the inner ear.” And, the pictures themselves are still “coarse” images in a tiny organ.
In his clinic, Dr. Hornibrook said, they are testing with tone-burst ECochG and applying intratympanic gadolinium for a scan the next day. “I can tell you already that tone-burst ECochG can detect hydrops well before it is visible on the scan,” he said.
Acute Attack Management
In other remarks, Dr. Hornibrook summarized the work of Leonardo Manzari, MD, of the MSA ENT Academy Center in Cassino, Italy, who was scheduled as a speaker but could not attend. Dr. Manzari has studied what is occurring physically during Meniere’s disease attacks.
“One important question for understanding the mechanism of Meniere’s disease is what is the status of the vestibular end-organs during an acute attack?” he said in a written summary of his work.
Ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) were measured in patients both during an attack and during a non-attack period. During attacks, his lab found, dynamic utricular function is enhanced, but saccular function is not similarly affected. “These results are to signify that a Meniere’s disease attack affects different otolithic regions differentially,” Dr. Manzari said in the summary. “A mechanical process rather than an ionic change in endolymph may be responsible for the MD attack.”