Revisiting the dissociation between singing and speaking in expressive aphasia

Abstract

We investigated the production of sung and spoken utterances in a non-fluent patient, C.C., who had a severe expressive aphasia following a right-hemisphere stroke, but whose language comprehension and memory were relatively preserved. In experiment 1, C.C. repeated familiar song excerpts under four different conditions: spoken lyrics, sung lyrics on original melody, lyrics sung on new but familiar melody and melody sung to a neutral syllable "la". In experiment 2, C.C. repeated novel song excerpts under three different conditions: spoken lyrics, sung lyrics and sung-to-la melody. The mean number of words produced under the spoken and sung conditions did not differ significantly in either experiment. The mean number of notes produced was not different either in the sung-to-la and sung conditions, but was higher than the words produced, hence showing a dissociation between C.C.'s musical and verbal productions. Therefore, our findings do not support the claim that singing helps word production in non-fluent aphasic patients. Rather, they are consistent with the idea that verbal production, be it sung or spoken, result from the operation of same mechanisms.

Preserved Singing in Aphasia

“…This interpretation is consistent with observations of isolable processing systems for speech and music (Hébert et al, 2003;Marin, 1982;Peretz & Coltheart, 2003;Peretz & Morais, 1993). KL's production errors are also consistent with this interpretation.…”

“…In contrast, KL's representation of verbally repeated phrases appeared more difficult to access, requiring a greater degree of verbal cueing and resulting in more frequent incomplete utterances. Overall, our findings may account for the previously reported paradoxical effect in the literature of preserved singing of familiar songs in patients with expressive aphasia, but the lack of an effect for unrehearsed sung over spoken novel stimuli in such patients (Cohen & Ford, 1995;Hébert et al, 2003;Peretz et al, 2004;Smith, 1966;Yamadori et al, 1977). In other words, melodic rehearsal appeared to be the key component for effecting longer-term improvements in speech production.…”

“…Cohen & Ford, 1995;Hébert et al, 2003;Peretz et al, 2004). Rehearsal was of paramount importance for KL's speech production, facilitating both melodic and nonmelodic phrases.…”

“…Recent researchers have built on Jackson's ideas, defining nonpropositional speech as conventionalized, context-dependent speech that does not involve syntactic parsing or the conscious formulation of new utterances to express a semantic message (Code, 1997;Nenonen, Niemi, & Laine, 2002;Speedie, Wertman, Ta'ir, & Heilman, 1993). The notion that singing represents a form of nonpropositional speech has received variable support (Hébert, Racette, Gagnon & Peretz, 2003). Notably, Speedie and colleagues (1993) described a case with preserved speech but impaired ability to swear, recite poetry, and sing previously well-known songs following a right basal ganglia lesion.…”

Cross-domain correlation in pitch perception, the influence of native language

“…On the one hand, several studies have found evidence suggesting autonomy of pitch processing in the two domains. Individuals with a disorder in one domain may have the other domain largely intact (Hébert, Racette, Gagnon, & Peretz, 2003;Peretz, Champod, & Hyde, 2003;Peretz & Coltheart, 2003;Racette, Bard, & Peretz, 2006;Schlaug, Marchina, & Norton, 2008;Ullman et al, 1997;Wilson, Parsons, & Reutens, 2006). Recent brain studies have pinpointed areas that are involved in linguistic pitch but not in music processing (Fedorenko, Behr, & Kanwisher, 2011).…”