“The so called brain stem auditory evoked potentials (BAEPs) are commonly abnormal in MSers and typically show evidence of slow conduction; this indicates that the brain is processing auditory signals more slowly. Although rudimentary we still use binaural (two ears) hearing for sound location; i.e. to ascertain where a signal is coming from. If one auditory pathway is conducting much slower than the other this interferes with this important brain function. This means MSers often have difficulty locating the source of a sound and how far away it is. You may think this is unimportant but is critical for avoidance reflexes that keep you alive. I can imagine MSers having more near misses when cycling in traffic if this important sense is impaired; MSers may have difficulty judging how far a car is from them when it approaches from behind. MSers also complain of having difficulty hearing when there is a lot of background noise. Our hearing system is very good at filtering out background noise and focusing on what needs to be heard; the so called cocktail party effect. MSers with auditory pathway involvement often lose the ability to follow conversations at ‘cocktail parties’ are in similar situations. MSers rarely have problems with sound perception (auditory hallucinations) or hear sounds that are not there (auditory illusions). These latter perceptual problems are usually due to MS lesions affecting the temporal lobe; the area of the brain that is responsible for auditory perception.”
“We seem to forget about the subtle impairments MSers have to live such as difficulty with sound location, tinnitus, hyperacusis, etc. This is another reason for us to stop MS causing damage in the first place. I would be interested to know if any of you have hearing problems.”
Lewis et al. Does interferon Beta-1a impact pure-tone hearing sensitivity among individuals with multiple sclerosis? J Neurosci Nurs. 2014 Dec;46(6):351-60.
OBJECTIVE: The purpose of the present investigation was to assess if individuals with multiple sclerosis (MS) taking intramuscular interferon beta-1a have significantly poorer hearing thresholds than those not currently using any disease-modifying therapies.
METHODS: This was a secondary analysis of data collected as part of two larger studies evaluating auditory function in MSers. The goal of this analysis was to determine if users of interferon beta-1a do not have significantly worse hearing thresholds than nonusers of disease-modifying therapies, after adjusting for potential confounders. A linear mixed model was fit to the audiometric thresholds of our subjects. This model included interferon beta-1a use, MS disease subtype, gender, test frequency, age, disease duration (number of years), and the Expanded Disability Status Scale score.
RESULTS AND CONCLUSIONS: With all subjects included, there is insufficient evidence to say that intramuscular interferon-beta 1a is not ototoxic (in relation to non-use of a disease-modifying therapy) at all frequencies tested except 3000 and 6000 Hz. After removing two influential subjects, the results indicated that there is statistical support for no ototoxic effect of intramuscular interferon beta-1a at test frequencies from 250 to 6000 Hz. There is insufficient evidence, however, to rule out an ototoxic effect at 8000 Hz. Future studies should further evaluate the effect of interferon on auditory function in patients with MS. Neuroscience nurses should monitor their patients’ hearing throughout the course of treatment.
Leite et al. Deafness in patients with multiple sclerosis. Audiol Neurootol. 2014;19(4):261-6.
Multiple sclerosis (MS) is a demyelinating disease and is considered the most debilitating neurological disorder among young adults. Sudden deafness has been reported in MSers. This article describes cases of sudden deafness related to acute bouts in MSers. A survey was conducted using 405 records of MSers attended to at a reference center in the city of Rio de Janeiro between 2011 and 2012 to identify cases of sudden deafness. Seven MSers were identified, 6 with a relapsing-remitting course and 1 with progressive disease at onset. Five MSers had unilateral deafness and 2 bilateral. The recovery was complete in 4 and partial in 1, and there was no recovery in 2 MSers. It was not possible to establish a topographical correlation between deafness and brainstem lesions. Audiometric examinations revealed severe hearing loss during the bout and recovery of hearing in 5 cases after remission.