engleski

Phnological impairments in people with aphasia

Phonemes differ in their inner differential features, which, present characteristics of certain phonemes in all world languages. In Croatian, there are eleven differential features. Phonological errors in aphasic person`s speech are related to difficulties in phonological encoding or remembering of the earlier saved lexical data. The survey is directed to the determination of differences in auditory and visual recognition of initial and final sound in words and nonwords, in people with aphasia. Two subtests of PALPA (Kay, Lesser, Colthert, 1992), Phonological Segmentation of Initial Sounds (16) and Phonological Segmentation of Final Sounds (17) were used for this research. The survey comprised 12 subjects (7 Broca’ s, 3 Wernicke’ s, 2 Conduction aphasia) of both genders, aged between 40 and 60. According to neurological findings (CT or MR) aphasia in all examinees was caused by left brain hemisphere damage. The study is conducted through eight variables. The variable Type of aphasia is excluded as criterial variable. Basic statistics was made for all variables. Differences between variables among the groups were estimated by ANOVA, T-Test for Independent Variables and by Paired Samples T-Test according to the program SPSS for Windows, Realise 10.0. All examinees have shown significant differences in recognition of initial and final sound in auditory and visually presented nonwords and words. Similar differences are confirmed according to the aphasia type. It seems that errors which were seen in most examinees are based on the lexical selection and the phonological planning. Similar to results from earlier studies (Blumstein, Baker and Goodglass, 1997a), examinees in our research made more errors in the perception of nonwords than real words, the overall patterns of performance are similar: 1) the perception of consonants is worse than that of vowels ; 2) more consonant perception errors occur when the test stimuli contrast by a single phonetic feature than when they contrast by two or more features ; and 3) among the various types of feature contrasts, the perception of articulation place contrasts and the perception of voicing contrasts are particularly vulnerable (according to Blumstein, 2001). This research has confirmed the presence of phonological impairments in people with aphasia. Examinees with Conduction aphasia produced a series of attempts to reach the target word. Every new attempt was more phonologically similar to target. These error patterns suggest that locus of the impairment may lie in the palling stages of speech production. The close phonological correspondence between the target word and the actual production suggests that the lexical target has been appropriately accessed and selected but that the phonological representation may not be appropriately activated. Examinees with Wernicke's aphasia often do not closely resemble the phonological structure of the target, and errors did not follow internal distinctive features of phonemes' pairs. Unlike Wernicke's and Conduction aphasia, Broca's aphasia examinees use inductive way of thinking in solving problems of lexical processing. Features of phonological errors, their position in the word, and errors like substitutions, omissions, additions and greater incidence point to impaired part of system in people with aphasia.

Phonological impairments; Broca's aphasia; Wernicke's aphasia; Conduction aphasia; Phonological segmentation

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