Background 1 2 3 4 6 Anatomy and physiology of the CANS Clinical evaluation of central auditory function requires understanding of the anatomy and physiology of the CANS and appreciation of its complexity. The CANS extends from the anterior and posterior cochlear nuclei which are situated on the surface of the inferior cerebellar peduncle to the auditory cortex. In between important structures through which nerve fibers pass are: the trapezoid body, the lateral lemniscus, the inferior colliculus, the medial geniculate body and the acoustic radiation of the internal capsule. The auditory cortex includes the gyrus of Heschl on the upper surface of the superior temporal gyrus, the planum temporale and the Silvian fissure. 7 8 Components of central auditory processing 9 10 Material and methods The medline research revealed 564 papers when using the keywords 'auditory deficits' and 'mental disorders'. 79 papers were referring specifically to CAPD in connection with mental disorders, as this is a new term for auditory deficits and one mostly used by audiologists. Auditory deficit is a more general term used mostly by psychiatrists. Both terms refer to the same disorder. It is essential to point out that 25 of the 79 papers are published between 2000 – 2003. Schizophrenia is found related to CAPD in 175 papers, 49 of them are published between 2000 – 2003 showing the research focus of the last three years. Learning disabilities were found related to CAPD in 126 papers. Parkinson's disease was related to CAPD in 29 papers. Dyslexia is related to CAPD in 88 papers, 37 of them are between 2000–2003. Alzheimer's disease and auditory deficits are connected in 39 papers. The remaining articles are on depression, alcoholism, anorexia and childhood mental retardation, all being related to some extend to CAPD. Assessment of the CANS is carried through a great variety of tests that fall into two main categories: psychoacoustic and electrophysiologic testing. Psychoacoustic tests are considered more subjective. Electrophysiologic ones are more objective with the exception of P300 component. Results psychoacoustic tests 11 12 13 14 15 16 17 18 19 20 21 electrophysiologic tests th  22 23 24 25 26 27 28 29 300  30 31 32 33 34 35 36 37 38 43 44 psychoacoustic and electrophysiologic testing according to type of lesion 45 46 47 48 49 50 51 52 Conclusions CANS assessment represents a fascinating field. Cooperation of professionals in psychiatry, neurology, neuropsychology and pediatric psychology, with the otolaryngologist-audiologist is a prerequisite. Central auditory processing disorders may co-exist with various mental disorders such as: learning disabilities, attention deficit hyperactivity disorder, dyslexia, autism, chronic alcoholism, Alzheimer's disease, adult autistic disorder, Schizophrenia, anorexia and mental retardation. Assessing these disorders is difficult due to the complex anatomy and physiology of the CANS. This explains the great variety of existing methods of testing with two main categories: those of psychoacoustic methodology and those based on electrophysiologic measures. Physiology of CANS is still not completely understood and further research is needed on development of new tests and validation of their clinical applicability. Conflict of interest none declared