Hearing Disorders
After Whiplash
This study sought to shed
some light on the problem of hearing loss or dysfunction after rear-end collisions.
The researchers started with 153 whiplash patients and 33 healthy control subjects,
and performed audiograms on these subjects. The audiogram tests the ability
of patients to recognize a pure tone. All patients were also asked about the
presence of hearing problems. Of the 153 whiplash patients, 14% were found to
have a hearing impairment "exceeding the 90th percentile of the ISO standards."
The researchers did not
stop here, however. Next, they took a group of 33 patients with chronic whiplash
pain with a duration of 3 years or more. These patients had no hearing loss
or minor hearing impairment, as based on the audiogram. They tested these subjects
and the controls using a "standardized speech-in-noise test." This test is more
useful, as, "Speech recognition is a perceptive-cognitive function, in contrast
to pure-tone hearing, which is a threshold identification function." The speech
recognition test (SRN) is more sensitive, and can provide more information to
the clinician.
After performing the SRN
test, the authors found that "40% of this subgroup of patients with WAD [whiplash
associated disorder] reported hearing problems. As many as 30% of the patients
with WAD had an abnormal SRN test result, as against 5% of the controls. Significant
relations were found between the SRN test and self-assessed hearing loss…"
The authors propose a number
of explanations as to how whiplash injuries can cause hearing dysfunction:
- "The trauma might cause
lesions other than the neck injury affecting the auditory system. Subliminal
injury of the cochlea, which is so delicate that conventional tests cannot
detect it, is quite possible. Lesions affecting the central auditory system,
from the brainstem to the temporal lobe cortex, are also conceivable…" although
less likely.
- The hearing problem
may be a "auditory stress disorder." "Most patients under stress have increased
tension of the neck muscles, as have patients with WAD."
- "A reflexogenic disturbance
from the neck via divergent afferent proprioceptive activity to the central
auditory nervous system might be an alternative explanation. Some support
for this theory is the single-photon emision computed tomography (SPECT) results
by Otte et al. this group found parieto-occipital hypoperfusion in a group
of patients with WAD and interpreted it as caused by activation of nociceptive
afferents from the upper cervical spine, sicne a group of patients with non-traumatic
chronic neck pain also showed parieto-occipital hypoperfusion."
No matter what the mechanism
of injury, this study demonstrates that the SRN is more accurate at uncovering
hearing problems than a simple audiogram, and that a significant percentage
of whiplash patients show signs of hearing dysfunction.
Tjell C, Tenenbaum A,
Rosenhall U. Auditory function in whiplash-associated disorders. Scandinavian
Audiology 1999;28:203-209.
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