Bilateral Hearing Loss is Associated With Decreased Nonverbal Intelligence in US Children Aged 6 to 16 Years

Objectives/Hypothesis: To evaluate the association between hearing loss and nonverbal intelligence in US children.
Study Design: The Third National Health and Nutrition Examination Survey (NHANES III) is a cross-sectional survey
(1988–1994) that used complex multistage sampling design to produce nationally representative demographic and examination
data.
Methods: A total of 4,823 children ages 6 to 16 years completed audiometric evaluation and cognitive testing during
NHANES III. Hearing loss was defined as low-frequency pure-tone average (PTA) >25 dB (0.5, 1, 2 kHz) or high-frequency
PTA >25 dB (3, 4, 6, 8 kHz) and was designated as unilateral or bilateral. Nonverbal intelligence was measured using the
Wechsler Intelligence Scale for Children-Revised block design subtest. Low nonverbal intelligence was defined as a standardized
score <4, two standard deviations below the standardized mean of 10.
Results: Mean nonverbal intelligence scores differed between children with normal hearing (9.59) and children with
bilateral (6.87; P5.02) but not unilateral (9.12; P5.42) hearing loss. Non-Hispanic black race/ethnicity and family income
<$20,000 were associated with 3.92 and 1.67 times higher odds of low nonverbal intelligence, respectively (odds ratio [OR]:
3.92; P<.001; OR: 1.67; P5.02). Bilateral hearing loss was independently associated with 5.77 times increased odds of low
nonverbal intelligence compared to normal hearing children (OR: 5.77; P5.02). Unilateral hearing loss was not associated
with higher odds of low nonverbal intelligence (OR: 0.73; P5.40).
Conclusions: Bilateral but not unilateral hearing loss is associated with decreased nonverbal intelligence in US children.
Longitudinal studies are urgently needed to better understand these associations and their potential impact on future
opportunities.