Abstract
As we listen to someone speaking, we extract both linguistic and non-linguistic information. Knowing how these two sets of information are processed in the brain is fundamental for the general understanding of social communication, speech recognition and therapy of language impairments. We investigated the pattern of performances in phoneme versus gender categorization in left and right hemisphere stroke patients, and found an anatomo-functional dissociation in the right frontal cortex, establishing a new syndrome in voice discrimination abilities. In addition, phoneme and gender performances were most often associated than dissociated in the left hemisphere patients, suggesting a common neural underpinnings.
Highlights
Speech perception is often seen as special (Liberman & Mattingly, 1989) because localized brain injury can elicit specific language impairments such as aphasia, and because healthy individuals are extremely efficient at categorizing phonemes and syllables despite large variations in the stimulus spectral patterns (Liberman, Delattre, & Cooper, 1952)
Based on functional MRI (Belin, et al, 2002, 2000; Charest et al, 2012) and Transcranial Magnetic Stimulation (Bestelemeyer, et al, 2011) results observed in healthy volunteers, we hypothesized that patients with right fronto-temporal stroke will show a deficit in gender categorization but intact phonological performances
Previous studies have reported cases of phonagnosia (Van Lancker & Canter, 1982; Van Lancker, Cummings, Kreiman, & Dobkin, 1988; Van Lancker, Kreiman, & Cummings, 1989), in which patients could not recognize familiar voices; but this deficit was associated with right parietal lesions
Summary
Speech perception is often seen as special (Liberman & Mattingly, 1989) because localized brain injury can elicit specific language impairments such as aphasia, and because healthy individuals are extremely efficient at categorizing phonemes and syllables despite large variations in the stimulus spectral patterns (Liberman, Delattre, & Cooper, 1952). For instance the literature describes increased memory for words spoken by familiar voices, compared to non-familiar voices (Nygaard & Pisoni, 1998; Nygaard, Sommers, & Pisoni, 1994; Palmeri, Goldinger, & Pisoni, 1993), and enhanced discrimination of, and memory for, (non-familiar) speakers of our own language compared to speakers of another language (Language Familiarity Effect e Perrachione & Wong, 2007) even in the absence of intelligibility (Fleming, Giordano, Caldara, & Belin, 2014) Most of these studies do not, address the issue of phoneme perception, and acoustical regularities coming from multiple levels are at play
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