Auditory agnosia

Auditory agnosia is a form of agnosia that manifests itself primarily in the inability to recognize or differentiate between sounds. It is not a defect of the ear or "hearing", but rather a neurological inability of the brain to process sound meaning. While auditory agnosia impairs the understanding of sounds, other abilities such as reading, writing, and speaking are not hindered.[1] It is caused by bilateral damage to the anterior superior temporal gyrus, which is part of the auditory pathway responsible for sound recognition, the auditory "what" pathway.[2]

Persons with auditory agnosia can physically hear the sounds and describe them using unrelated terms, but are unable to recognize them. They might describe the sound of some environmental sounds, such as a motor starting, as resembling a lion roaring, but would not be able to associate the sound with "car" or "engine", nor would they say that it was a lion creating the noise.[3] All auditory agnosia patients read lips in order to enhance the speech comprehension.[4]

It is yet unclear whether auditory agnosia (also called general auditory agnosia) is a combination of milder disorders, such auditory verbal agnosia (pure word deafness), non-verbal auditory agnosia, amusia and word-meaning deafness, or a mild case of the more severe disorder, cerebral deafness. Typically, a person with auditory agnosia would be incapable of comprehending spoken language as well as environmental sounds. Some may say that the milder disorders are how auditory agnosia occurs. There are few cases where a person may not be able to understand spoken language. This is called verbal auditory agnosia or pure word deafness.[5] Nonverbal auditory agnosia is diagnosed when a person’s understanding of environmental sounds is inhibited. Combined, these two disorders portray auditory agnosia.[6] The blurriness between the combination of these disorders may lead to discrepancies in reporting. As of 2014, 203 patients with auditory perceptual deficits due to CNS damage were reported in the medical literature, of which 183 diagnosed with general auditory agnosia or word deafness, 34 with cerebral deafness, 51 with non-verbal auditory agnosia-amusia and 8 word meaning deafness (for a list of patients see[7]).

  1. ^ Slevc, L.R.; Shell, A.R. (2015). "Auditory agnosia". The Human Auditory System - Fundamental Organization and Clinical Disorders. Handbook of Clinical Neurology. Vol. 129. pp. 573–587. doi:10.1016/B978-0-444-62630-1.00032-9. ISBN 9780444626301. PMID 25726291. Retrieved 9 December 2021.
  2. ^ Poliva O, Bestelmeyer PE, Hall M, Bultitude JH, Koller K, Rafal RD (September 2015). "Functional Mapping of the Human Auditory Cortex: fMRI Investigation of a Patient with Auditory Agnosia from Trauma to the Inferior Colliculus" (PDF). Cognitive and Behavioral Neurology. 28 (3): 160–80. doi:10.1097/WNN.0000000000000072. PMID 26413744. S2CID 913296.
  3. ^ Martin GN (2006). Human neuropsychology. Harlow, England; New York: Pearson/Prentice Hall. ISBN 978-0-13-197452-4. OCLC 61692682.
  4. ^ Buchman AS, Garron DC, Trost-Cardamone JE, Wichter MD, Schwartz M (May 1986). "Word deafness: one hundred years later". Journal of Neurology, Neurosurgery, and Psychiatry. 49 (5): 489–99. doi:10.1136/jnnp.49.5.489. PMC 1028802. PMID 2423648.
  5. ^ Buchtel, H.A. (2002). "Auditory Agnosia". Encyclopedia of the Human Brain: 285–287. doi:10.1016/B0-12-227210-2/00011-X. ISBN 9780122272103. Retrieved 9 December 2021.
  6. ^ Simons, J.S.; Ralph, M.A.L. (1999). "Previous Cases: The Auditory Agnosias" (PDF). Neurocase. 5: 379–406. doi:10.1093/neucas/5.5.379. Retrieved 9 December 2021.
  7. ^ Poliva O (2014). Neuroanatomical and perceptual deficits in auditory agnosia: a study of an auditory agnosia patient with inferior colliculus damage (Ph.D. thesis). Prifysgol Bangor University. pp. 67–74.