The Treatment by Small Dose of Valproic Acid for Auditory Hypersensitivity in Autism Spectrum Disorder

Introduction: The children of autism spectrum disorder (ASD) suffer from various complications. Auditory hypersensitivity (AH) is one of them. The mechanism is not clear and effective treatments are not found. Some reports suggest that AH is caused by decreased inhibitory processing resulting from abnormal sensory gating system or dysfunction of inhibitory interneurons, and the abnormalities in the GABAergic interneurons and/or in the serotonin/dopamine system. We report here our experience to treat AH in ASD children by a small dose of valproic acid (VPA).

Materials and Methods: A total of seven children (two males, M: 1 and 2; and five females, F, 1–5) of ASD with severe AH from the age of 5 to 11 years. They were suffered from noises of vacuum cleaner, noises at platform, echo in a pool, siren of ambulance etc. Six cases took Yokukansan (Japanese herbal medicine with serotonergic functions) at first, as emotional stabilizer, but not effective for AH. F-2 took VPA as the initial treatment for AH. VPA was used with the dose of 5.1 to 8.3 mg/kg/day.

Results: In all cases, AH phenomena became milder (F-3, -4, -5) or disappeared (F-1, -2, M1,2). F-1 who suffered from various noises, especially sound to wash out in a lavatory became free from earmuffs, the monthly panic in F-2 triggered by a chime of microwave oven, sound of boiled water, etc., disappeared within a month.

Conclusion: The treatment by small dose of VPA for AH in ASD showed successful effects, This treatment has a value to be tried.