Neuropsychology in Alzheimer's Disease and Dementia Research
Purpose of Review: This review describes a variety of neuropsychological dementia studies published between January 2004 and June 2005. In selecting articles for description in the present paper, our goal was not a comprehensive review of what is an enormous and growing literature, but rather to select and describe individual interesting studies from a sufficient range of dementia-related topics to permit illustration of some of the important questions for which a neuropsychological perspective aids in the understanding of dementias.
Recent Findings: Findings in the studies reviewed include a variety of different topics. Some of the themes include the following: (a) Alzheimer's disease is the most common cause of dementia, but a large body of research documents that there are important cognitive differences among various types of dementia, (b) the emerging research is also important in demonstrating the need for more sensitive clinical screening measures, (c) cognitive data are strongly predictive of functional decline, and (d) subtle declines in verbal learning appear to precede clinical Alzheimer's disease.
Summary: Neuropsychological data are key to progress in understanding and developing more effective treatments for Alzheimer's disease and other dementia. For instance, efforts to identify early markers of dementia will be a key component to development of early intervention strategies.

According to a 2004 report from the US Center for Disease Control, dementia was the eighth leading cause of death in the USA in 2001; this figure probably even underestimates the mortality attributable to dementia, as many people with dementia develop other medical conditions which may then be listed as the primary cause of death. At least 37 million people are currently living with Alzheimer's disease or another dementia. Approximately 1% of the population aged 60-64 years has Alzheimer's disease, but the prevalence approximately doubles every 5 years after age 60, so that the prevalence among those age 85 years and older is estimated at approximately 30-45%. Given that the average life span is increasing, and that the risk of most forms of dementia increases with advancing age, a higher proportion of the population may experience some form of dementia before death than in past generations.

There have been considerable advances in the understanding of Alzheimer's disease and other dementias over the past several decades, but fully effective treatments and preventive strategies await further research. There are ongoing research efforts to clarify the distal and proximal etiologies (including underlying environmental, genetic and other biologic risk factors, and neuropathology) of Alzheimer's disease and other dementias. The hope is that the understanding yielded from such research will result in interventions to slow the course and/or manage symptoms of those with dementia, and even to identify early interventions and preventive strategies. Neuropsychological test results may play an important role in developing this knowledge; for example, attention to different cognitive profiles may be helpful in the process of identifying meaningful distinctions among the dementias, as well as providing potential means of early detection, and understanding the process of functional decline.

This review describes some of the neuropsychological dementia research over the past 18 months (January 2004 to June 2005). The literature on neuropsychological deficits in dementia is enormous and ever growing. Our intention with the present paper was not to provide a comprehensive review all of the neuropsychological studies of dementia, nor even the (still quite large) subset published between 2004 and 2005. Rather, in selecting articles for description in the present paper, our goal was to select and describe individual interesting studies from a sufficient range of dementia-related topics to permit illustration of some of the variety of questions for which a neuropsychological perspective aids in the understanding of Alzheimer's disease and other dementias. Topics we consider here include use of neuropsychological data in clarifying distinctions among types of dementia, early cognitive markers of dementia, efforts to develop time-efficient yet sensitive cognitive measures for clinical screening of dementia, and the relationship of cognitive deficits to functional decline in dementia.