Balancing Effortful and Errorless Learning in Naming Treatment for Aphasia

Study 1: Evaluate the benefits of balancing effortful and errorless learning via adaptive naming deadlines.

• Study design: The investigators will enroll 30 people with aphasia in a randomized within-subjects crossover design comparing trained words in three retrieval conditions. Stimuli will be balanced across conditions using an established item-response theory algorithm developed by Dr. Hula (consultant). Participants will receive 8 sessions of treatment per condition (2x/ week for 4 weeks), with probes administered at baseline and 1 week, 3 months, and 6 months post-treatment. Condition treatment order will be randomly assigned and counter- balanced across participants. In total, Sub-study 1 includes two initial assessment sessions, 24 treatment sessions and 24 baseline and follow-up probe assessment sessions per participant over a 10-month period. Data collection will take place at the Language Rehabilitation and Cognition Laboratory (LRCL) at the University of Pittsburgh, in participants' homes, or in private rooms in public spaces (e.g. libraries, community centers).

• Participants: The investigators will recruit 30 male and female community-dwelling people with aphasia >6 months post- onset of aphasia due to unilateral left-hemisphere stroke. Aphasia diagnosis will be confirmed by Comprehensive Aphasia Test (CAT) performance and medical history. Investigators will exclude potential participants with right hemisphere stroke, other neurological disease, significant psychiatric disorder, severe motor speech disorder, or active substance dependence.

• Assessment Procedures: Participants will be tested on a comprehensive initial battery of standardized assessments characterizing their aphasia severity and overall language profile, naming and discourse abilities, semantic processing, verbal short-term and working memory at baseline. Patient-reported measures of treatment motivation and pre-post changes in communication effectiveness will also be measured in response to each treatment condition. These tests will ensure that our participants well-characterized from a behavioral perspective, and measures will be used in secondary analyses and model development exploring predictors of treatment response.

• Treatment description: Each training trial will consist of a fixation cross and picture presentation. A repetition cue (audio recording and written from of the target) will be provided to participants based on the deadlines described above. Participants will be instructed to name the picture and indicate when they have given their final answer via key press, with responses also timed and scored by clinician key press. In the errorless condition, they will be instructed to repeat the target, while in the other conditions they will be asked to try to name the picture independently before they hear the target. Once they have indicated that they have provided their final answer, they will receive accuracy feedback on the computer screen based on clinician scoring. To maximize the clinical relevance of this study, investigators will control total amount of treatment time (8 hours) between conditions, instead of controlling the total number of trials. This is because many more trials can be completed per hour in the errorless or balanced conditions compared to the effort-maximized condition, and investigators want study outcomes to practically inform clinicians on how best to spend limited treatment time.