Implicit learning and implicit treatment outcomes in individuals with aphasia

ABSTRACT

Background: Implicit learning is a process of learning that occurs outside of conscious awareness and may be involved in implicit, exposure-based language training. However, research shows that implicit learning abilities are variable among individuals with aphasia, and it remains unknown whether individuals who show basic implicit learning abilities also benefit from implicit language training.

Aims: The aims of this series of experiments were to test implicit learning in individuals with agrammatic aphasia, examine the effects of a novel implicit language treatment, and investigate whether individuals with aphasia who show implicit learning ability also benefit from implicit treatment focused on passive sentence comprehension.

Methods & Procedures: Nine participants with chronic agrammatic aphasia and 21 neurologically intact participants completed a visuomotor serial reaction time test of implicit learning (Experiment 1). The participants with aphasia also completed a short-term novel implicit sentence comprehension treatment (Experiment 2) that consisted of five sessions of repeated exposure to grammatically correct passive sentences and matching photographs. Sentence comprehension was tested in multiple baseline sessions and on each day of training using a sentence–picture matching task. The relation between participants’ learning patterns across experiments was also examined.

Outcomes & Results: Individuals with agrammatic aphasia as well as neurologically intact adults demonstrated significant implicit sequence learning in the serial reaction time task. However, the participants with aphasia did not show concomitant improvement in sentence comprehension as a result of the implicit treatment protocol.

Conclusions: This study suggests that individuals with agrammatic aphasia demonstrate implicit learning ability; however, this ability does not necessarily promote successful outcomes in treatment that is based solely on implicit training methods.

KEYWORDS:

• Agrammatic aphasia
• implicit learning
• implicit treatment
• serial reaction time task
• sentence comprehension

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Institute On Deafness and Other Communication Disorders of the National Institutes of Health (NIH) [award number F31DC013204 (J. Schuchard)], [award number R01DC001948 (C. K. Thompson)], and [award number P50DC012283 (C. K. Thompson)]; and by Northwestern University, Evanston, IL, USA [Graduate Research Grant to J. Schuchard]. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.