Remembering to remember: The neuroscience of memory interventions

By Alice Jack, Assistant Psychologist at Brainkind Kerwin Court

Memory rehabilitation after acquired brain injury

Memory is a cognitive process that allows us to encode, store, and retrieve information.

It underpins many everyday activities, from remembering routine tasks to recognising familiar people.

The neural networks supporting memory include the hippocampus, medial temporal lobes, and frontal cortex. However, the widespread nature of these networks also contributes to their vulnerability following acquired brain injury (ABI).

Memory is among the most commonly reported cognitive impairments after traumatic brain injury and approximately 77 per cent of stroke survivors report ongoing memory difficulties.

These difficulties can substantially affect activities of daily living, relationships, mood, and employment.

Given their prevalence and functional impact, a range of approaches are used to support memory after brain injury.

Understanding how these approaches work, and how effective they are, is essential to effective rehabilitation.

How does the brain recover from injury?

Some recovery can occur spontaneously after stroke or traumatic brain injury.

Animal research has shown, for example, that performance on motor tasks may improve after cortical damage, even in the absence of formal rehabilitation.

One key mechanism underlying spontaneous recovery is diaschisis reversal.

Diaschisis refers to reduced metabolism and blood flow in brain regions that are structurally intact but functionally connected to damaged areas.

In the early stages after injury, this disruption is often reversible, allowing function to improve as neural activity normalises.

Another contributor to early impairment and recovery is cerebral oedema, or swelling in the brain.

Swelling can disrupt neural functioning, but over time the brain’s glymphatic and vascular drainage systems help reduce excess fluid.

Medical interventions may also support this process in the acute phase.

While neurons lost after ABI cannot be regenerated, the brain can adapt by reorganising and recruiting alternative neural pathways to achieve the same functional outcome.

This process, known as neuroplasticity, allows individuals to reach the same “goal” using different routes.

Repetition and intensive practice strengthen synaptic connections and support both spontaneous recovery and longer-term reorganisation. These principles underpin memory rehabilitation.

Restorative approaches: returning to pre-injury functioning

Restorative approaches aim to improve memory by directly strengthening the neural pathways underlying impaired cognitive processes.

A commonly studied method is computer–assisted cognitive rehabilitation (CACR), which involves repeated practice of structured tasks targeting specific domains such as memory or attention.

Jung and colleagues investigated CACR in people with ABI who completed 30 sessions over six weeks.

Participants showed improvements on several measures, including verbal list learning, recall, figure memory, and visual digit span.

These findings suggest that targeted, repetitive practice can lead to measurable gains in both verbal and visual memory.

There is also evidence that CACR may be associated with neural changes.

In a case study, Nordvik and colleagues reported increased white matter integrity following CACR, with improved integrity in anterior right -hemisphere pathways associated with better working memory performance.

This provides preliminary support for CACR-related- neuroplasticity.

However, evidence for CACR is inconsistent. Several studies have failed to demonstrate clear benefits, particularly when outcomes relate to everyday functioning rather than trained tasks.

For example, one study found improvements in digit span, visual span, and learning after five weeks of CACR poststroke, but no additional benefit compared with controls on activities of daily living.

Such inconsistencies may reflect differences in intervention duration and intensity, outcome measures, types of memory targeted, and participant characteristics, including severity and type of injury.

Therefore, while CACR may improve performance on specific tests, its real-world impact may vary between individuals.

Compensatory approaches

Compensatory approaches focus on improving everyday functioning rather than restoring memory processes and structures.

This may involve supporting individuals to develop systems or routines, such as regularly recording and reviewing information in a diary, to compensate for memory difficulties that persist after recovery or restorative training.

These approaches are most commonly used in memory rehabilitation and are typically divided into internal and external strategies.

Internal strategies

Internal strategies involve mentally manipulating information to enhance encoding and retrieval, often by adding meaning and encouraging deeper processing.

Examples include visualisation, mental rehearsal and the method of loci, which involves mentally placing information along a familiar route.

O’Neil, -Pirozzi and colleagues evaluated internal strategies by comparing a group who received 12 sessions of strategy training with a control group who received no active intervention.

Participants who received training showed greater improvements on the Rivermead Behavioural Memory Test, an assessment reflecting everyday memory demands such as remembering appointments or delivering messages.

Importantly, improvements were maintained one month after training ended.

External strategies

External strategies involve storing information outside the mind using tools such as diaries, notebooks, calendars, smartphones or reminder systems.

These approaches reduce cognitive load and support recall through external cues.

Diary use is commonly recommended in memory rehabilitation and has been shown to reduce self–reported memory problems, improve appointment attendance, and increase work productivity.

A factor linked to effectiveness is remembering to use external aids consistently.

Technological advances have helped address this issue by providing automated prompts and reminders.

Bos and colleagues found that smartphone–based memory aids led to greater improvements in memory than using traditional notebooks.

Another study found that participants continued smartphone use after the intervention ended, suggesting good longer–term acceptability.

However, concerns such as battery life and dependency on technology were also reported.

A holistic approach

Because each approach has strengths and limitations, combining techniques may lead to better outcomes.

A meta-analysis by Lambez and Vakil concluded that the strongest memory improvements were observed when internal and external strategies were used together, rather than in isolation.

In conclusion

Although the brain cannot fully rebuild itself after ABI, memory rehabilitation can promote neuroplasticity and improve everyday functioning.

Restorative approaches, such as CACR, alongside compensatory strategies including internal and external aids, play an important role in supporting memory.

The effectiveness of memory rehabilitation is influenced by factors including motivation and engagement in rehabilitation, which can be affected by mood; while reduced insight into memory difficulties may limit strategy use.

Research is complicated by the inclusion of heterogeneous injury types and severities, and variation in memory domains targeted.

As a result, there is still no consensus on which approaches work best for whom, or at what stage after injury they are most effective.

Future research may help clarify these questions, including how memory strategies can be better integrated into everyday life and how long any benefits are sustained.