TABLE 1.

Etiology of unilateral and asymmetric hearing loss in children.

Causes of unilateral hearing loss	Prevalence among all children with unilateral hearing loss (%)	Reference
Unknown/No risk factors	31–54	(Declau et al., 2008; Ghogomu et al., 2014)
Congenital causes	45	(Ghogomu et al., 2014)
Cochlear nerve deficiency	26–50	(Clemmens et al., 2013; Nakano et al., 2013)
Developmental delay	21	(Haffey et al., 2013)
Premature birth	20	(Haffey et al., 2013)
Low birth weight	6–20	(Declau et al., 2008; Haffey et al., 2013)
Hereditary	3–11	(Declau et al., 2008; Ghogomu et al., 2014)
Hyperbilirubinemia	5–11	(Declau et al., 2008; Friedman et al., 2013; Haffey et al., 2013)
In utero infections	3–7	(Declau et al., 2008; Friedman et al., 2013; Ghogomu et al., 2014)
Craniofacial anomalies	5	(Declau et al., 2008)
Deafness syndrome	4	(Declau et al., 2008)
Low APGAR score	2	(Declau et al., 2008)
Acquired causes
Ototoxic medication/Intravenous antibiotic use	3–21	(Declau et al., 2008; Friedman et al., 2013; Haffey et al., 2013)
Prolonged NICU stay	14–20	(Friedman et al., 2013; Haffey et al., 2013)
Mechanical ventilation	4–17	(Declau et al., 2008; Friedman et al., 2013; Haffey et al., 2013)
Meningitis	3–5	(Ghogomu et al., 2014; Haffey et al., 2013)
Head trauma	3–4	(Ghogomu et al., 2014; Haffey et al., 2013)