Table 4.

Summary of studies investigating the effects of mercury exposure in children and adults.

Reference	Study Design	Population	Procedures	Results
Shargorodsky et al. (2011) [25]	Cross-sectional without a control group	Adults	Pure-tone audiometry	No association found.
Discalzi et al. (1993) [61]	Cross-sectional with a control group	Adults	ABR	Workers exposed to mercury had significantly increased I–V IPL compared to an age- and gender-matched non-exposed control group.
Al-Batanony et al. (2013) [91]	Cross-sectional with a control group	Adults	Pure-tone audiometry	Significant difference in the prevalence of hearing loss between workers exposed to mercury and the non-exposed control group.
Rothwell and Boyd (2008) [93]	Cross-sectional without a control group	Adults	Pure-tone audiometry	The number of dental amalgam fillings by surface area had a significant association with hearing thresholds at 8, 11.2, 12.5, 14, and 16 kHz.
Dutra et al. (2010) [95]	Cross-sectional with a control group	Adolescents	Central Auditory processing	Significant difference between groups for the results of sequential memory of nonverbal stimuli. Significant difference for temporal frequency, duration pattern, and staggered spondaic word tests. No significant difference between groups for the sequential memory of verbal stimuli and sound localization. No significant difference for speech test with competitive white noise.
Counter et al. (1998) [96]	Cross-sectional without a control group	Children and adults	Pure-tone audiometry and ABR	Significant correlation between the hearing threshold at 3 kHz in the right ear and blood lead level in children. No effect on ABR results found.