Understanding the neuropsychological syndrome of dementia

The syndrome of dementia is most commonly caused by Alzheimer's disease (AD), an age-related neurodegenerative process that primarily affects the cortex. Approximately 4 million Americans carry the diagnosis, and the number is expected to rise to 14 million by the year 2040. Affected individuals suffer multiple cognitive deficits that progressively affect the ability to communicate. Typically the earliest symptom is impairment of episodic memory, but other forms of declarative memory are ultimately impaired. To understand the communication problems of individuals with Alzheimer's, clinicians need to understand disease effects on knowledge stores and cognitive and memory processes. Using spared memory systems and less effortful cognitive processes to compensate for impaired stores and processes is the primary means by which optimal care can be provided. Recent advances in our understanding of disease effects on semantic memory suggest a greater potential for habilitation than previously thought. In this article, the neuropathology of AD is reviewed, effects on cognitive and communicative functions are specified, and principles for providing optimal patient care are discussed.