Question
Could you go over the post synaptic mechanism of ANSD?
Answer
A post-synaptic form of auditory neuropathy spectrum disorder (ANSD) is dysfunction of the auditory nerve or (theoretically) the synapse between the inner hair cells and the afferent auditory nerve fibers. The term usually means that the nerve is not capable of being effectively activated with electrical stimulation. In some cases, however, the dysfunction is post-synaptic (neural) but the nerve is reasonably intact and simply not capable of responding to stimulation with abrupt and transient sounds (like clicks and perhaps tone bursts). Chuck Berlin coined the term "auditory dys-synchrony" for these patients.
The 1996 article by Starr and colleagues along with the 2008 Guidelines on ANSD provide good explanations of the post-synaptic mechanism.
References
Starr, A., Picton, T.W., Sininger, Y., Hood, L.J., & Berlin C.I. (1996). Auditory neuropathy. Brain, 119, 741-753.
Guidelines for identification and management of infants and young children with auditory neuropathy spectrum disorder. (2008). Available from the Bill Daniels Center for Children’s Hearing, The Children’s Hospital, Colorado, USA and at https://www.childrenscolorado.
This Ask the Expert was asked as a follow up question to Dr. Hall's course, Clinical Applications of Electrocochleography Today, which can be accessed in the AudiologyOnline Course Library.
