Cognitive Strategy Training at Home Shows Very Large Effects After Brain Injury

For the millions of people who survive a stroke or traumatic brain injury each year, the most stubborn obstacles to recovery are often invisible. While paralysed limbs and unsteady gait attract immediate clinical attention, the cognitive aftershocks—faltering attention, scrambled planning, unreliable memory—frequently go unrecognised until a person returns home and discovers they can no longer send an email, brew a pot of coffee, or pull on a sweater without help. A new study published in the Scandinavian Journal of Occupational Therapy offers striking evidence that a structured, home-based cognitive intervention can restore exactly these kinds of everyday abilities, with effects the authors describe as very large.

The research, led by M. Ø. Lindstad and colleagues at the Norwegian University of Science and Technology, Oslo Metropolitan University and Oslo University Hospital, tested the Perceive, Recall, Plan and Perform (PRPP) Intervention in three adults over the age of 67 who were receiving home-based rehabilitation after acquired brain injury. Rather than a traditional clinical trial, the team used single-case experimental designs with multiple baselines, a methodology well suited to rehabilitation research where participants are heterogeneous and recruiting large groups is difficult. Each participant acted as their own control, with repeated measurements taken during staggered baseline phases before the intervention was introduced, allowing the researchers to demonstrate a functional relationship between treatment and improvement.

The PRPP system is grounded in an information-processing model of cognition. It frames everyday task performance as a continuous loop of four processes: perceiving incoming sensory information, recalling stored knowledge, planning and evaluating responses, and monitoring performance as the task unfolds. The assessment stage catalogues how a person applies 35 observable cognitive strategies—called descriptors—during a chosen activity, rating each as efficient, questionable or ineffective. The intervention stage then works on those weak links directly. Therapists use a structured prompting sequence, ‘Stop, Attend, Sense, Think, Do’, deploying verbal, visual or physical cues calibrated to each client’s cognitive profile. As the client grows more proficient, the therapist deliberately withdraws support, transferring control of the strategies to the client so that they can be generalised across tasks and settings.

Crucially, the intervention took place where cognitive difficulties actually bite: in participants’ own homes. Three Norwegian municipal home-based rehabilitation teams delivered the programme, which consisted of nine sessions over three weeks. Each participant selected one personally meaningful task as the focus of treatment. For one participant, pseudonymised as Helge, the goal was to write and send an email independently—something that had become laborious and error-prone since his brain injury. For Georg, it was putting on a sweater, a task that had defeated him despite his physical capability, apparently due to insecurity and learned non-use of intact skills. For Frank, it was brewing coffee, a multi-step activity in which he would omit critical steps such as filling the water reservoir or inserting the filter.

The results were measured with the PRPP Assessment Stage 1, which scores percent task mastery from 0 to 100, with independence set at a cut-off above 85 percent. Visual analysis of graphed data across baseline, intervention, post-intervention and follow-up phases was complemented by Tau-U, a statistical technique that combines non-overlap between phases with trend analysis within the intervention phase. All three participants showed clear improvements in task mastery, with 70 to 100 percent of intervention and follow-up data points exceeding baseline levels. Individual Tau-U values ranged from 0.8 to 1.0, and the weighted average across participants reached 0.94 for task mastery when baseline was compared with post-intervention and follow-up phases—a magnitude classified as a very large effect.

Equally important, the gains held. Improvements persisted immediately after the intervention ended and again at follow-up four weeks later, even though the therapists had by then withdrawn all prompting. Georg achieved full independence in dressing and scored beyond his expected goal on Goal Attainment Scaling, a change with ripple effects: he could get out of bed and stay warm in his wheelchair without waiting for home care staff, easing pressure on an entire morning routine. Frank maintained performance above the independence threshold four weeks after his final session and managed untrained tasks, such as collecting post from a locker and pouring coffee into a thermos, using the strategies he had acquired. His Barthel Index score had already been at the maximum of 20, illustrating a limitation of broad functional measures in capturing task-specific change.

Not every outcome was uniform. Helge achieved 100 percent task mastery only intermittently during follow-up, fluctuating between complete independence and partial dependence on the email task. The authors suggest that intellectual familiarity with a cognitive strategy is not the same as internalising it, and that the meaningfulness of the task itself may have played a role. Helge was approaching retirement, and the email task was anchored to a working identity that was fading; his motivation, they note in light of prior rehabilitation research, may have shifted accordingly. His residual difficulties clustered in the planning quadrant, and errors in follow-up were mostly about time efficiency rather than accuracy—yet he still reported confidence in sending emails on his own.

The study addresses a well-documented gap. Recent Cochrane reviews concluded that evidence for occupational therapy in cognitive impairment after stroke, and for cognitive rehabilitation in adults with acquired brain injury, remains insufficient and of low quality—drawn mostly from hospital settings and often from computer-based remediation aimed at impairments rather than real-world function. Evidence-based guidelines instead favour performance-focused, strategy-based, compensatory approaches, precisely the category into which the PRPP Intervention falls. Meanwhile, community-based occupational therapists, particularly generalists in small municipalities, report lacking the specialised competencies and evidence-based tools they need to serve clients with cognitive challenges. A system designed to apply across diagnoses, ages, severities and contexts could fill that void, though the authors caution that adoption requires cultural change within services and funding for the specialised PRPP training.

The authors are candid about limitations. Data collection by the therapists who delivered the intervention introduces potential bias, although blinded inter-observer agreement checks on 20 percent of sessions mostly exceeded the 80 percent acceptability threshold. Frank completed only eight sessions and fewer follow-up measurements than planned, partly because of impatience once he considered himself independent, though his perfectly stable baseline and daily independent performance partially offset the missing data. Crucially, the generalisation of cognitive strategies to untrained tasks could not be conclusively established, because new tasks were measured at only a single point. The Barthel Index, moreover, proved too coarse an instrument for home-based contexts, hitting ceiling effects and missing the richer activities that matter in daily life.

Even so, the study’s ecological validity is its signature strength. By measuring outcomes on the very tasks participants needed and wanted to perform, in the environments where they live, the research captures the kind of functional change that laboratory-based cognitive training often fails to deliver—and that randomised trials with underpowered samples have struggled to demonstrate. Single-case experimental designs, the authors argue, can generate robust evidence close to ordinary clinical practice even with small numbers, and they call for systematic replication, including multiple-baseline designs across behaviours within participants, to test whether strategy use truly transfers to novel and more complex activities. If the very large effects observed here hold up across that replication series, a structured prompting method delivered in a client’s own kitchen or living room may become one of the most practical weapons yet against the hidden cognitive toll of brain injury.

Subject of Research: Effectiveness of the PRPP cognitive strategy intervention for task performance in home-based rehabilitation after acquired brain injury

Article Title: Effectiveness of the PRPP Intervention after brain injury in home-based rehabilitation: Single-case experimental designs with multiple baselines

Article References: Lindstad, M. Ø., Obstfelder, A., Sveen, U., & Stigen, L. (2025). Effectiveness of the PRPP Intervention after brain injury in home-based rehabilitation: Single-case experimental designs with multiple baselines. Scandinavian Journal of Occupational Therapy, 32(1), Article 2444591. https://doi.org/10.1080/11038128.2024.2444591

Image Credits: AI Generated

DOI: 10.1080/11038128.2024.2444591

Keywords: cognitive rehabilitation, PRPP Intervention, acquired brain injury, home-based rehabilitation, occupational therapy, cognitive strategy use, task mastery, single-case experimental design, stroke, Tau-U, evidence-based practice, Effectiveness