How dual-task interference on word production is modulated by the timing of the secondary task: evidence from errors in people with aphasia

ABSTRACT

Background

Utterance production is affected under dual-task conditions, but so far studies have shown an impact either on lexical or on phonological processes, but not on both simultaneously.

Aims

In the present study, we aimed at investigating how interference on lexical and phonological encoding is modulated by the timing of the concurrent task and by the attentional requirement (divided vs focused attention).

Methods

Participants with aphasia (PWA) underwent a picture naming task and an auditory detection task, with auditory stimuli presented at different stimulus onset asynchronies (SOAs). The dual-task was performed under divided (Experiment 1) and focused attention (Experiment 2).

Outcome & Results

Omission errors increased under dual-task at early SOA only in Experiment 1 while phonological errors increased at later SOAs in both experiments.

Conclusion

These patterns of errors indicate that lexical and phonological processes are impacted under dual-task conditions, giving rise to an increase of specific types of errors at specific SOAs. They also show that very mild anomia may be more severe when assessed under dual-task conditions.

KEYWORDS:

• Dual-task
• word production
• interference
• attention
• aphasia

Disclosure statement

No potential conflict of interest was reported by the author(s).

Declaration of interest statement

The authors confirm the absence of any conflict of interest.

Notes

¹ In the Appendix 1, the PWA from both experiments are presented (experiment 1 and 2). The last two columns indicate which experiments have been performed by the participants, as some of them didn’t perform both.

² As mixed errors and neologisms could have different origins (Friedmann et al., 2013), analyses were also performed without neologisms and mixed errors. As the results were unchanged, we kept them in the analyses.

³ The experiments were not designed to be analysed together but an analysis was run on the merged data from the two experiments. The interaction between conditions and experiment on RTs was significant. F(3,5256.2)=31.745, p<.001, thus further motivating the separate analysis of Experiment 1 and Experiment 2.

⁴ As mixed errors and neologisms could have different origins (Friedmann et al., 2013), analyses were also performed without neologisms and mixed errors: the results were unchanged and we kept these errors in the analyses.