Phonagnosia
Phonagnosia (from the Greek φώνημα phonema "voice" and αγνώσις agnosis " agnosia , non-recognition") denotes the inability to recognize the identity of people from their voice. A distinction is made between phonagnosia as a result of brain damage and congenital phonagnosia.
Historical overview
Phonagnosia has hardly been studied in science to this day. The term phonagnosia was first used by Van Lancker and Canter (1982), neuroscientists from the USA. They examined brain-damaged patients and found deficits in three areas:
- Some patients have had difficulty identifying people from their voices (phonagnosia).
- Some patients have had difficulty identifying a person they know from their face ( prosopagnosia ).
- Some patients had difficulty assigning names to known people.
In 2009, British scientists reported the first case of congenital phonagnosia (Garrido et al., 2009). It has long been suspected that there is a congenital phonagnosia, since prosopagnosia also occurs in a congenital and an acquired form (McConachie, 1976).
In Leipzig, a test battery is currently being developed at the Max Planck Institute for Human Cognitive and Brain Sciences in order to be able to diagnose phonagnosia in German-speaking subjects in the future.
Symptoms
People who have phonagnosia cannot recognize other people by their voice.
KH, a 60-year-old management consultant with congenital phonagnosia, reports that she cannot even recognize her daughter's voice on the phone (Garrido et al., 2009). KH has normal hearing and intelligence. However, KH is able to recognize people by other characteristics, e.g. B. on the face.
The impairment of voice perception affects communication over the telephone in particular. KH avoids spontaneous telephone calls and only accepts previously agreed telephone calls. In doing so, she resorts to cognitive strategies that help her to deal better with the perceptual disorder.
It is likely that other areas of everyday life are also affected. For example, you need the ability to recognize voice if you want to find out who is talking in the next room. It is also helpful in radio interviews or radio plays to be able to assign the voices to the different speakers. However, it is still unclear whether these are the areas with which phonagnosicians have difficulties.
It should be emphasized that in the case of a phonagnosic perception disorder, the recognition of familiar melodies ( amusia ) and the faces of known people (prosopagnosia) as well as the assignment of non-verbal noises are normally not impaired.
Types of phonagnosia
Just like prosopagnosia (the inability to identify people by their face), phonagnosia distinguishes between two types.
Phonagnosia as a result of brain damage
Van Lancker et al. (1982) examined the ability to recognize voice in brain-damaged patients. They distinguished between two types of impaired voice recognition:
- the inability to recognize familiar voices (phonagnosia)
- the inability to distinguish two unknown voices from each other
The recognition of known voices can be viewed independently of the differentiation of voices. It is believed that the two processes are based on different neuroanatomical structures.
In the case of the inability to recognize familiar voices, only right-hemispherical regions appear to be damaged. On the other hand, the differentiation between unknown voices can be disturbed if areas of the right or the left hemisphere are damaged.
Congenital Phonagnosia
The first scientific studies on congenital phonagnosia were carried out in 2009 on the British patient KH. She does not suffer from any neurological disease, has no brain damage and has normal hearing. In a 2014 by Roswandowitz et al. conducted study, two otherwise completely healthy test subjects with congenital phonagnosia could be identified from a random sample. The test subjects AS and SP showed deficits in voice recognition, but no abnormalities could be found in auditory and visual control tests or in a neuropsychological assessment. Structural changes in the brain were excluded using structural magnetic resonance imaging . These results suggest that congenital phonagnosia is a modality-specific developmental disorder in which only speech recognition is severely restricted.
In the Garrido et al. (2009) it turned out that KH is not able to differentiate voices known from the media from unknown voices. Even after a training phase in which voices should be “learned” from unknown people, KH failed to recognize these voices. The experiments show that KH has difficulty recognizing voices even without acquired neuronal damage. The same deficits were found in the test persons AS and SP. Both also showed limitations in assessing pitch , but were able to correctly identify the timbre .
In the case of congenital prosopagnosia, sufferers are often unaware that they have difficulty recognizing faces. Often times they don't find out until reading reports from proso diagnoses. KH, on the other hand, noticed very early on that she had difficulty recognizing voices. It is so far unclear to what extent affected phonagogues are aware of their perceptual disorder. Phonagnostics often learn compensation strategies, for example by interpreting contextual information and characteristic language patterns.
According to initial estimates, the prevalence of congenital phonagnosia is 0.2% of the German-speaking population.
literature
- P. Belin, S. Fecteau, C. Bedard: Thinking the voice: Neural correlates of voice perception . In: Trends in Cognitive Sciences , 8 (3), 2004, pp. 129-135.
- V. Bruce, A. Young: Understanding face recognition . In: British Journal of Psychology , 77, 1986, pp. 305-327.
- AM Burton, V. Bruce, RA Johnston: Understanding face recognition with an interactive activation model . In: British Journal of Psychology , 81, 1990, pp. 361-380.
- L. Garrido, F. Eisner, C. McGettigan, L. Stewart, D. Sauter, JR Hanley, JDW Schweinberger, B. Duchaine: Developmental phonagnosia: A selective deficit of vocal identity recognition . In: Neuropsychologia , 47, 2009, pp. 123-131.
- HR McConachie: Developmental prosopagnosia. A single case report . In: Cortex , 12, 1976, pp. 76-82.
- F. Neuner, SR Schweinberger: Neuropsychological impairments in the recognition of faces, voices, and personal names . In: Brain and Cognition , 44, 2000, pp. 342-366.
- K. von Kriegstein, O. Dogan, M. Grüter, AL Giraud, C. Kell, T. Grüter, A. Kleinschmidt, SJ Kiebel: Simulation of talking faces in the human brain improves auditory speech recognition . In: Proceedings of the National Academy Sciences , 105 (18), 2008, pp. 6747-6752.
- DR Van Lancker, GJ Canter: Impairment of voice and face recognition in patients with hemispheric damage . In: Brain and Cognition , 1, 1982, pp. 185-195.
- DR Van Lancker, J. Kreiman: Voice discrimination and recognition are separate abilities . In: Neuropsychologia 25 (5), 1987, pp. 829-834.
- DR Van Lancker, JL Cummings, J. Kreiman, BH Dobkin: Phonagnosia: A dissociation between familiar and unfamiliar voices . In: Cortex 24, 1988, pp. 195-209.
- DR Van Lancker, J. Kreiman, JL Cummings: Voice perception deficits: Neuroanatomical correlates of phonagnosia . In: Journal of Clinical and Experimental Neuropsychology 11 (5), 1989, pp. 665-674.
- Nilofar Elhami: Who is speaking? In: Berliner Zeitung , 2009
Web links
- Information University College London
- Voice recognition test Max Planck Institute for Human Cognitive and Brain Sciences
Individual evidence
- ↑ a b Roswandowitz et al .: Two Cases of Selective Developmental Voice-Recognition Impairments . In: Current Biology , 2014, doi: 10.1016 / j.cub.2014.08.048
