September 16, 2008

MRI Detects Soft Tissue Damage Affecting Kids' Hearing

TUESDAY, Sept. 16 (HealthDay News) -- Soft-tissue defects that contribute to hearing loss in children can be detected using MRI, say U.S. researchers who analyzed the medical records of hundreds of children diagnosed with sensorineural (related to sensory nerves) hearing loss.

Radiography, including computed tomography (CT) and X-rays, is often used to look for bone structures problems in children with hearing loss. However, defects in the soft tissue within the bones may also cause hearing loss.

Of the 170 children in this study, ages one month to 17 years, 101 (59 percent) had hearing loss in both ears and 69 (41 percent) had hearing loss in one ear, adding up to 271 ears with sensorineural hearing loss. All the children had MRIs, which revealed:

• 108 ears (40 percent) with inner ear abnormalities.
• 87 ears (32 percent) with abnormalities of the cochlea, a spiral structure containing hair cells vital to hearing. Of those 87 ears, 63 (23 percent) had mild abnormalities of the cochlea, and 24 (9 percent) had moderate to severe abnormalities.
• 49 ears (18 percent) had either missing (53 percent) or deficient (47 percent) cochlear nerves.
• Ears with severe and profound hearing loss had more abnormalities (48 percent) than those with moderate hearing loss (29 percent).
• Children with moderate, severe or profound hearing loss in one ear had more inner ear abnormalities (62 percent) than those with hearing loss of the same severity in two ears (38 percent).

The findings, by researchers at UT Southwestern Medical Center and Children's Medical Center Dallas, were published in the September issue of the journal Archives of Otolaryngology -- Head & Neck Surgery.

"Although the specific origin of sensorineural hearing loss may remain undiagnosed in many patients, a thorough workup to identify the cause of sensorineural hearing loss should be considered in each patient," the study authors wrote. "Historically, high-resolution CT has been the imaging modality of choice in the initial workup of these patients. However, the soft tissue structures of the inner ear responsible for the electrochemical transfer of sound to the brain, such as the membranous labyrinth and the cochlear nerve, are not evaluated well with high-resolution CT."

"With MRI, these soft tissue components of hearing from the cochlea to the auditory cortex can be elucidated, which should improve our ability to appropriately diagnose the location of the defect in these children with sensorineural hearing loss," they concluded.

More information

The American Academy of Family Physicians has more about hearing loss in children.

-- Robert Preidt
SOURCE: JAMA/Archives journals, news release, Sept. 15, 2008
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