Participants receive Communication Bridge™, a multi-component, participation-focused, dyadic intervention in which both the person with PPA and their co-enrolled communication partner are intervention recipients. Communication Bridge™ is modelled on the Living with Aphasia: Framework for Outcome Measurement (A-FROM) and the Care Pathway Model that was developed for persons living with primary progressive aphasia. Consistent with participation-focused intervention models personally salient training stimuli are incorporated into all therapy activities in the Experimental arm.

The Control arm includes a non-dyadic intervention in which the person with PPA is the active intervention recipient and their communication partner is in a supporting role. In the Control arm, participants receive a speech-language intervention designed to address impairment and functional limitations, comprised of activities that address word retrieval and 'automatic' speech production using fixed, non-personalized, stimuli across participants.

Evidence-based speech language therapy treatment will be compared and contrasted in the two arms of the study.

Goal Attainment Scaling, a 7-point rating scale with -3 representing 'no longer participating' and +3 representing 'exceeded goal'. Higher scores indicate better progress in goal achievement.

The CPIB measure is a 10-item, disorder-generic, Likert scale that asks persons to rate how their condition interferes with participating in daily communication activities (e.g., talking to people you know/do not know, securing a turn in a fast-moving conversation). The psychometric properties of the measure have been published previously (Baylor et al., 2013; Baylor et al., 2019). Both raw and T-scores are available. The CPIB T-score has a theoretical mean of 50 and standard deviation of 10 with higher numbers reflecting higher levels of participation in communication activities.

The MBI is a pen/paper Likert scale with 16 items distributed across three subscales (Montgomery et al., 1985) completed by the care partner. Total and mean item scores are calculated for each of the three subscales: Objective burden is defined as the perceived infringement of disruption of tangible aspects of a caregiver's life; Subjective demand/relational burden is typically described as the extent to which the caregiver perceives that the care recipient is overly demanding in the context of caregiving; Subjective stress burden is the emotional impact of caregiving responsibilities. Participants rate each item with a score between 1 (Not at all) and 5 (A great deal) corresponding to the amount of perceived burden. Higher scores reflect increased burden. Internal consistency .81 to .90. Construct validity demonstrated in mixed cohort of care partners of persons with dementia. Test-retest stability coefficients are robust (ICC of 0.92 to 0.91) (Farley et al., 2010).