Atypical prosopagnosia following right hemispheric stroke: A 23-year follow-up study with M.T.

ABSTRACT

Most findings on prosopagnosia to date suggest preserved voice recognition in prosopagnosia (except in cases with bilateral lesions). Here we report a follow-up examination on M.T., suffering from acquired prosopagnosia following a large unilateral right-hemispheric lesion in frontal, parietal, and anterior temporal areas excluding core ventral occipitotemporal face areas. Twenty-three years after initial testing we reassessed face and object recognition skills [Henke, K., Schweinberger, S. R., Grigo, A., Klos, T., & Sommer, W. (1998). Specificity of face recognition: Recognition of exemplars of non-face objects in prosopagnosia. Cortex, 34(2), 289–296]; [Schweinberger, S. R., Klos, T., & Sommer, W. (1995). Covert face recognition in prosopagnosia – A dissociable function? Cortex, 31(3), 517–529] and additionally studied voice recognition. Confirming the persistence of deficits, M.T. exhibited substantial impairments in famous face recognition and memory for learned faces, but preserved face matching and object recognition skills. Critically, he showed substantially impaired voice recognition skills. These findings are congruent with the ideas that (i) prosopagnosia after right anterior temporal lesions can persist over long periods > 20 years, and that (ii) such lesions can be associated with both facial and vocal deficits in person recognition.

KEYWORDS:

• Face recognition
• prosopagnosia
• voice recognition
• anterior temporal lobe

Acknowledgements

We would like to express our deep gratitude to M.T. for volunteering to participate in this investigation in such a co-operative way and for kindly giving us insight into his life with prosopagnosia in a number of discussions that accompanied this investigation. Additionally, we thank the control participants for their time and cooperation in this investigation. Thanks go also to Mareike Grotheer, Bettina Kamchen and Kathrin Rauscher for various forms of technical support during the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Where legal conditions do not permit public archiving of anonymized study data, we will grant access to named individuals in accordance with ethical procedures governing the reuse of clinical data, upon completion of a formal data sharing agreement and approval of the local ethics committee. Readers seeking access to stimuli and data are advised to contact the last author. No part of the study procedure or analyses was pre-registered prior to the research being conducted. We report how we determined our sample and sample size, all data exclusions, all inclusion/exclusion criteria, and all manipulations.

Notes

1 Given the small number of trials and the fact that M.T. has performed at ceiling for happy faces on other occasions (e.g., Henke et al., 1998), we caution against interpreting this particular finding.

2 Table S2 shows that when considering (potentially biased) hit and false alarm rates, M.T. shows enhance false alarms to voices. This finding is reminiscent of studies on healthy participants which report inflated proportions of “familiar only” decisions to voices (compared with faces; e.g., Hanley et al., 1998), and which discuss the degree to which these might relate to ambiguity or perceptual uncertainty in the voice domain.

Additional information

Funding

This research was partially supported by the Deutsche Forschungsgemeinschaft, Research Unit Person Perception to SRS, grant reference FOR1097.