Center for Health Policy and Research (CHPR) Publications


Acoustic stapedius muscle reflex in mercury-exposed Andean children and adults

UMMS Affiliation

Department of Pediatrics; Shriver Center; Center for Health Policy and Research; Intellectual and Developmental Disabilities Research Center

Publication Date


Document Type



Adolescent; Adult; Aged; Aged, 80 and over; Auditory Threshold; Child; Ecuador; Environmental Exposure; Environmental Illness; Evoked Potentials, Auditory, Brain Stem; Female; Humans; Incidence; Male; Mercury; Middle Aged; *Mining; Reflex, Acoustic; Young Adult


Environmental Public Health | Otolaryngology | Otorhinolaryngologic Diseases | Pediatrics | Pharmacology, Toxicology and Environmental Health | Speech Pathology and Audiology


OBJECTIVES: Hg exposure has been associated with hearing impairment and brainstem anomalies. Acoustic stapedius reflex (ASR) thresholds, growth functions, decay/adaptation times, and behavioral auditory thresholds were used to screen Andean children and adults for Hg-induced auditory brainstem and facial nerve impairment.

METHODS: Fifty-one participants, which included 22 children (aged 6-17 years) and 29 adults (aged 19-83 years) living in gold mining areas of Ecuador where Hg is widely used in amalgamation, were screened using ASR immittance procedures.

RESULTS: Mean blood mercury (HgB) level in the children was 15.6 mug/L (SD, 21.3; median, 7 mug/L; range, 2.0-89 mug/L), and in the adults 8.5 mug/L (SD, 7.1; median, 6 mug/L; range, 2.0-32 mug/L). Mean contralateral ASR thresholds (ASRT) for the screening frequency of 2000 Hz in the children (39 ears) was 92.9 dB HL (SD, 6.1; range, 80-105 dB HL), and in the adults (53 ears) 90.0 dB HL (SD, 6.4; range, 65-105 dB HL). The ASRT in the children increased significantly with HgB level (rho = 0.433; p = 0.008).

CONCLUSION: The results suggested mercury (Hg)-induced anomalies in the brainstem-mediated acoustic stapedius muscle reflex in children.

DOI of Published Version



Counter SA, Buchanan LH, Ortega F. Acoustic stapedius muscle reflex in mercury-exposed Andean children and adults. Acta Otolaryngol. 2012 Jan;132(1):51-63. doi: 10.3109/00016489.2011.617778. Epub 2011 Dec 18. PubMed PMID: 22175530; PubMed Central PMCID: PMC3490497. Link to article on publisher's site

Journal/Book/Conference Title

Acta oto-laryngologica

Related Resources

Link to Article in PubMed