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; P = .02) but not unilateral (9.12; P = .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; P = .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; P = .02). Unilateral hearing loss was not associated with higher odds of low nonverbal intelligence (OR: 0.73; P = .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.