Improvement in hearing after chiropractic care: a case series

BACKGROUND: The first chiropractic adjustment given in 1895 was reported to have cured deafness. This study examined the effects of a single, initial chiropractic visit on the central nervous system by documenting clinical changes of audiometry in patients after chiropractic care. CASE PRESENTATION: Fifteen patients are presented (9 male, 6 female) with a mean age of 54.3 (range 34–71). A Welch Allyn AudioScope 3 was used to screen frequencies of 1000, 2000, 4000 and 500 Hz respectively at three standard decibel levels 20 decibels (dB), 25 dB and 40 dB, respectively, before and immediately after the first chiropractic intervention. Several criteria were used to determine hearing impairment. Ventry & Weinstein criteria of missing one or more tones in either ear at 40 dB and Speech-frequency criteria of missing one or more tones in either ear at 25 dB. All patients were classified as hearing impaired though greater on the right. At 40 dB using the Ventry & Weinstein criteria, 6 had hearing restored, 7 improved and 2 had no change. At 25 dB using the Speech-frequency criteria, none were restored, 11 improved, 4 had no change and 3 missed a tone. CONCLUSION: A percentage of patients presenting to the chiropractor have a mild to moderate hearing loss, most notably in the right ear. The clinical progress documented in this report suggests that manipulation delivered to the neuromusculoskeletal system may create central plastic changes in the auditory system.