Contribution of psychoacoustics and neuroaudiology in revealing correlation of mental disorders with central auditory processing disorders.

BACKGROUND: Psychoacoustics is a fascinating developing field concerned with the evaluation of the hearing sensation as an outcome of a sound or speech stimulus. Neuroaudiology with electrophysiologic testing, records the electrical activity of the auditory pathways, extending from the 8th cranial nerve up to the cortical auditory centers as a result of external auditory stimuli. Central Auditory Processing Disorders may co-exist with mental disorders and complicate diagnosis and outcome. DESIGN: A MEDLINE search was conducted to search for papers concerning the association between Central Auditory Processing Disorders and mental disorders. The research focused on the diagnostic methods providing the inter-connection of various mental disorders and central auditory deficits. MEASUREMENTS AND MAIN RESULTS: The medline research revealed 564 papers when using the keywords 'auditory deficits' and 'mental disorders'. 79 papers were referring specifically to Central Auditory Processing Disorders in connection with mental disorders. 175 papers were related to Schizophrenia, 126 to learning disabilities, 29 to Parkinson's disease, 88 to dyslexia and 39 to Alzheimer's disease. Assessment of the Central Auditory System is carried out through a great variety of tests that fall into two main categories: psychoacoustic and electrophysiologic testing. Different specialties are involved in the diagnosis and management of Central Auditory Processing Disorders as well as the mental disorders that may co-exist with them. As a result it is essential that they are all aware of the possibilities in diagnostic procedures. CONCLUSIONS: Considerable evidence exists that mental disorders may correlate with CAPD and this correlation could be revealed through psychoacoustics and neuroaudiology. Mental disorders that relate to Central Auditory Processing Disorders are: Schizophrenia, attention deficit disorders, Alzheimer's disease, learning disabilities, dyslexia, depression, auditory hallucinations, Parkinson's disease, alcoholism, anorexia and childhood mental retardation. Clinical awareness should be high in order for doctors of the two specialties, psychiatry and otorhinolaryngology-audiology to collaborate.