Aphasia and auditory extinction: Preliminary evidence of binding

Effects of Acquired Aphasia on the Recognition of Speech Under Energetic and Informational Masking Conditions

Persons with aphasia (PWA) often report difficulty understanding spoken language in noisy environments that require listeners to identify and selectively attend to target speech while ignoring competing background sounds or “maskers.” This study compared the performance of PWA and age-matched healthy controls (HC) on a masked speech identification task and examined the consequences of different types of masking on performance. Twelve PWA and 12 age-matched HC completed a speech identification task comprising three conditions designed to differentiate between the effects of energetic and informational masking on receptive speech processing. The target and masker speech materials were taken from a closed-set matrix-style corpus, and a forced-choice word identification task was used. Target and maskers were spatially separated from one another in order to simulate real-world listening environments and allow listeners to make use of binaural cues for source segregation. Individualized frequency-specific gain was applied to compensate for the effects of hearing loss. Although both groups showed similar susceptibility to the effects of energetic masking, PWA were more susceptible than age-matched HC to the effects of informational masking. Results indicate that this increased susceptibility cannot be attributed to age, hearing loss, or comprehension deficits and is therefore a consequence of acquired cognitive-linguistic impairments associated with aphasia. This finding suggests that aphasia may result in increased difficulty segregating target speech from masker speech, which in turn may have implications for the ability of PWA to comprehend target speech in multitalker environments, such as restaurants, family gatherings, and other everyday situations.

Verbal short-term memory and language impairments in Cantonese speakers after stroke

PURPOSE

The study examined the relationship between verbal short-term memory (STM) and language impairment in Cantonese speakers after stroke. It is hypothesised that Cantonese speakers with left-hemisphere (LH) stroke would perform worse than those with right hemisphere (RH) stroke and normal controls. Specific linguistic factors of Cantonese might affect results in the tasks.

METHOD

Fifteen participants with LH stroke, 10 with RH stroke and 25 healthy controls were tested with auditory-verbal immediate serial recall (ISR) tasks and auditory linguistic tasks. All stroke participants were assessed with the Cantonese version of Western Aphasia Battery (CAB).

RESULT

The LH group performed significantly worse than the RH and healthy control groups in the auditory verbal ISR and auditory linguistic tasks. There were significant lexicality, frequency and imageability effects in most tasks. Auditory discrimination and word comprehension tasks, but not the auditory word recognition task had correlations with ISR tasks.

CONCLUSION

Verbal STM and language performance of Cantonese-speakers with history of LH stroke were inferior to RH stroke and healthy controls. The effects of lexicality, word frequency and imageability on verbal STM memory performance were found. Cantonese tones have effects on performance in auditory word recognition task, similar to onset, nucleus and rime.

Processamento auditivo e afasia: uma revisão sistemática

A avaliação do Processamento Auditivo (PA) é um procedimento audiológico que fornece informações importantes relacionadas ao processo de compreensão do material linguístico. Com o objetivo de investigar as pesquisas que abordam a interface PA – Afasia foi realizada uma revisão sistemática tomando por referência os seguintes descritores e seus correlatos em língua inglesa: Afasia, Dicótico, Monótico, Processamento auditivo e Habilidades auditivas; a busca foi realizada no formato intersecção com o conectivo and. Os cinco estudos incluídos nesta pesquisa diferem em aspectos diversos nos seus objetivos, tais como localização da lesão, mudança da dominância hemisférica para linguagem, presença de vantagem da orelha esquerda em quadros de afasia, relação entre habilidades auditivas e linguagem e a extinção auditiva. Os trabalhos analisados sugerem que as abordagens acerca do processamento auditivo e afasia ocorreram sob duas perspectivas de funcionamento cortical: teoria localizacionista e teoria distribucionista, estando a maioria dos artigos (três), em consonância com a primeira corrente (localizacionista).

Further evidence of auditory extinction in aphasia

PURPOSE

Preliminary research (Shisler, 2005) suggests that auditory extinction in individuals with aphasia (IWA) may be connected to binding and attention. In this study, the authors expanded on previous findings on auditory extinction to determine the source of extinction deficits in IWA.

METHOD

Seventeen IWA (M(age) = 53.19 years) and 17 neurologically intact controls (M(age) = 55.18 years) participated. Auditory stimuli were spoken letters presented in a free-field listening environment. Stimuli were presented in single-stimulus stimulation (SSS) or double-simultaneous stimulation (DSS) trials across 5 conditions designed to determine whether extinction is related to binding, inefficient attention resource allocation, or overall deficits in attention. All participants completed all experimental conditions.

RESULTS

Significant extinction was demonstrated only by IWA when sounds were different, providing further evidence of auditory extinction. However, binding requirements did not appear to influence the IWA's performance.

CONCLUSIONS

Results indicate that, for IWA, auditory extinction may not be attributed to a binding deficit or inefficient attention resource allocation because of equivalent performance across all 5 conditions. Rather, overall attentional resources may be influential. Future research in aphasia should explore the effect of the stimulus presentation in addition to the continued study of attention treatment.

Attention and other cognitive deficits in aphasia: presence and relation to language and communication measures

PURPOSE

This study was designed to further elucidate the relationship between cognition and aphasia, with a focus on attention. It was hypothesized that individuals with aphasia would display variable deficit patterns on tests of attention and other cognitive functions and that their attention deficits, particularly those of complex attention functions, would be related to their language and communication status.

METHOD

A group of individuals with varying types and severity of aphasia and a group of age- and education-matched adults with no brain damage completed tests of attention, short-term and working memory, and executive functioning.

RESULTS

Overall, the group with aphasia performed significantly more poorly than the control group on the cognitive measures but displayed variability in the presence, types, and severity of their attention and other cognitive deficits. Correlational and regression analyses yielded significant relations between participants' attention deficits and their language and communication status.

CONCLUSION

The findings accorded well with prior research identifying (a) attention and other cognitive deficits in most but not all individuals with aphasia; (b) heterogeneity in the types and severity of attention and other cognitive symptoms among individuals with cognitive impairments; and (c) potent associations among attention, language, and other cognitive domains. Implications for clinical practice and future research are discussed.