Cognitive interventions in early Alzheimer’s disease and mild cognitive impairment

In Australia, the role of a clinical neuropsychologist within dementia-related services mainly focuses on issues of diagnosis, carer support and decision-making capacity. This partly reflects financial and time constraints in the employment and use of neuropsychology services, but may also indicate hesitancy in devoting effort to cognitive intervention for a degenerative disorder - i.e., will it work?

Reasons for optimism

Encouragingly, recent studies have used interventions based on well documented psychological research to evaluate the usefulness of memory training and rehabilitation for declining memory. As a result, cognitive interventions for early dementia are increasingly considered as realistic options in the neuropsychologist's toolkit.

There are at least two major reasons for this positive movement. Firstly, in Alzheimer's disease (AD), which is the most common form of dementia, the earliest and most prominent impairment is in the learning and remembering of new information (episodic memory). By contrast, components of memory that rely on well learnt knowledge or procedures (implicit memory), such as playing the piano or cooking well learnt recipes, remain intact much longer. Many of the cognitive interventions for AD rely on this dissociation, and even people with moderate to severe dementia can learn and retain some new information and skills (e.g., Camp, Bird & Cherry, 2000). Through a large body of recent psychological research, we now have a better understanding of the intact and impaired aspects of memory and cognition in different stages of AD, which gives us confidence in developing more effective intervention techniques.

The second major impetus for offering cognitive intervention is the increasingly early diagnosis of AD and identification of risk factors, including biomarkers (Fotuhl, Hachinski, & Whitehouse, 2009) and mild cognitive impairment (MCI; see boxed information). This shift in detection of the early stages of AD has opened up opportunities for implementing cognitive interventions targeted to improve features of emerging dementia.

To date, no effective medication has been found for MCI, and even in early AD medications have limited impact (small improvements can be noted in approximately 50 per cent of people but mostly in attention rather than in the core problem of memory function). Additionally, medication side effects are common. In contrast, cognitive intervention directly addresses patient and family requests for assistance and is a relatively low cost strategy for managing the everyday cognitive difficulties typically seen.

Early cognitive intervention programs: Do they work?

Through a meta-analysis of 19 studies, Sitzer, Twamley and Jeste (2006) provided positive support for the value of cognitive intervention in improving cognitive and functional abilities for people with AD. This positive view is reinforced by a recent randomised controlled trial (Clare et al., 2010) in which people with early AD were allocated to a cognitive rehabilitation group or a control group of relaxation or no treatment. Cognitive rehabilitation consisted of eight weekly sessions focused on addressing participant-generated goals relevant to their everyday life. The intervention included learning about external aids, strategies for learning new information and maintaining attention, as well as techniques for stress management. As compared to the control groups, large improvements were found following cognitive rehabilitation in achieving participant-relevant goals in everyday activities.

A focus on improving everyday activities as opposed to performance on cognitive tests is clearly important and one that we have pursued with people with mild memory difficulties (MCI). We recently reported our own experience running a randomised controlled trial of a memory intervention for people with MCI and their families (Kinsella et al., 2009). The intervention consisted of five weekly group sessions conducted by experienced neuropsychologists. Strategies included managing attention, specific techniques for learning new information, use of external aids and coping strategies. The intervention demonstrated a significant effect on everyday memory performance, with the intervention group performing better than the wait-list group at both post-test and follow-up. Importantly, family members also reported an increase in their own knowledge of strategy use following the group (see Jean et al., 2010) for a recent review of similar studies).

Most of these intervention studies combine multiple strategies within the intervention program. Although this reflects the accepted philosophy that different strategies will be needed for different everyday goals and tasks, at the same time this approach makes it difficult to discern if some techniques are generally more effective than other techniques. What is now needed is more information about what strategy works most effectively for specific everyday tasks.

A specific technique for specific problems: Spaced retrieval

Successful memory interventions in MCI and early AD often rely on using the implicit memory system, which is not primarily impaired. Methods involving elimination or reduction of errors during learning, termed ‘errorless learning' are widely believed to capitalise on the relative preservation of implicit memory, and can be more effective than trial-and-error methods (Baddeley & Wilson, 1994). Spaced retrieval is a form of errorless learning, which assists people to remember simple (but important) information for very long periods and has become the cornerstone of many intervention programs for AD and MCI. It was introduced as an intervention for people with AD by Camp and colleagues (Camp, 2001) and involves actively retrieving information to be recalled at progressively lengthened intervals.

Spaced retrieval is a technique that can be learnt by people with mild memory difficulties to boost their everyday memory (e.g., learning the names of new members in the yoga class), or is a simple method that families or carers can use with people with more impaired memory to help keep track of day-to-day tasks (e.g., teaching new residents in nursing homes the route to the dining room). It has been used to effectively train face-name pairings, recall of personal information, object-location associations, prospective memory, and instrumental activities of daily living in people with mild dementia (see, for example, Camp et al., 2000). Spaced retrieval is one memory strategy that all neuropsychologists should consider when working with people with memory impairment.

Future directions

While indications for the efficacy of cognitive interventions in AD and MCI are positive, a great deal more work will need to be carried out over longer time frames to assess meaningful outcomes such as reduction in care needs and maintenance of community living status. Treatment approaches for degenerative conditions other than typical AD, including semantic dementia, frontal variant frontotemporal dementia and posterior cortical atrophy, will also need to be developed as these conditions become increasingly understood and more frequently diagnosed.

The principal author can be contacted at [email protected].