A case study of reproduction conduction aphasia I: Word production

Phonology: A Review and Proposals from a Connectionist Perspective

“…Because functors (closed class words) have little meaning and are primarily of grammatic importance, they normally receive little top-down reinforcement from semantic representations. Thus, in patients capable of strong lexical-semantic bias (no anomia), the repetition of major lexical items may be superior to that of functors, whereas in patients with anomia, major lexical items should have much less advantage over functors as then, neither receives much top-down reinforcement (Caplan, Vanier & Baker, 1986). On the other hand, functors should be relatively resistant to phonemic paraphasias because of their strong instantiation in sequence knowledge acquired through frequent use (see ''Frequency Effects'' below).…”

“…Also, because the lesion reduces the reliability of bringing every one of multiple syllables above production threshold, this increases the opportunity for sublexical omissions. Such effects are well documented in patients with reproduction conduction aphasia (Alajouanine & Lhermitte, 1973;Bub, Black, Howell, & Kertesz, 1987;Caplan, Vanier, & Baker, 1986;Caramazza, Miceli, & Villa, 1986;Dubois et al, 1973;Friedman & Kohn, 1990;Gandour, Akamanon, Dechongkit, Khunadorn, & Boonklam, 1994;Kohn, 1989Kohn, , 1991Kohn, , 1995McCarthy & Warrington, 1984;Pate, Saffran, & Martin, 1987;Valdois et al, 1988;Yamadori & Ikumura, 1975). On the other hand, repetition of long words is less likely to result in verbal paraphasias because a single phonemic error is less likely to generate patterns of activity corresponding to other real words, with their associated top-down reinforcement effects.…”

“…On the other hand, functors should be relatively resistant to phonemic paraphasias because of their strong instantiation in sequence knowledge acquired through frequent use (see ''Frequency Effects'' below). This has been borne out in practice (Caplan, Vanier, & Baker, 1986;Kohn, 1989;Lecours, 1982). To summarize, the relative advantage in repetition of functors over major lexical items will reflect the balance of two factors: degree of preservation of representations of phonemic sequence knowledge supporting word frequency effects (favoring functors) and naming ability (favoring major lexical items).…”

“…In addition, the lexical effect in repetition of real words may paradoxically have a corrupting influence as the damaged connections from concept representations to the acousticarticulatory motor pathway serve as an additional potential source of phonemic paraphasias (through damage to pathway 4; Fig. 3) (Caplan, Vanier & Baker, 1986;Dubois et al, 1973;Martin, Lesch, & Bartha, 1999). To the extent that the acousticarticulatory motor pathway is damaged and pathways from concept representations are spared, lexical bias effects are increased and repetition of nonwords is impaired.…”

The Selective Impairment of Phonological Processing in Speech Production

“…They note that patients who make (almost) exclusively semantic Hillis, Rapp, Romani, & Caramazza, 1990) or phonological errors (Caplan, Vanier, & Baker, 1986;Hillis, Boatman, Hart, & Gordon, 1999;Wilshire & McCarthy, 1996) cannot be fit by their model when lesioned globally. However, Dell et al raise various methodological reasons as to why the performance of some of these problematic cases for their model should be discounted.…”