Understanding Neurology

46MemoryThere are many different forms of memory, bothconscious (explicit) and unconscious (implicit).Explicit memory may refer to episodic memories (i.e.learning new information, or recalling discreteepisodes such as previous holidays), or semanticmemory (i.e. the database of knowledge we draw onto give meaning to our conscious experience).Practically, assessing memory as part of neuropsychologicaltesting usually involves asking thepatient to learn new information, and then testingrecall after a delay. Semantic memory is also assessed,but there is considerable overlap with language.The Wechsler Memory Scale-Revised comprisesvarious subscales, which assess different componentsof memory. Verbal memory is tested using logicalmemory, which involves the patient reading a storyparagraph, and then having to recall as much aspossible. Verbal paired associates involve thepresentation of pairs of words. At recall, one word isshown, and the patient must provide the other wordin the pair. Nonverbal memory may be assessed in asimilar fashion, but by asking for recall of sequencesof taps rather than a story. Short-term verbal memoryis assessed using digit span.A further measure of nonverbal memory is theRey–Osterrieth complex figure (40). This is anabstract design, which is not easily encoded verbally.The ability to copy the Rey figure is a measure ofvisuo-perceptual function. The ability to draw frommemory after a 30-minute delay is a measure ofdelayed nonverbal memory.Perception and construction abilitiesWhile perception involves all sensory modalities, inpractice the neuropsychologist is interested in visualand auditory perception.Visual perception and constructionObject and face recognition, colour perception, andvisual search activities may all be assessedneuropsychologically.The Benton Facial Recognition Test involves thepatient being shown one face, with six others on theadjacent page, one of which matches the target, andis a measure of facial recognition. The Judgement ofLine Orientation Test involves a test line having to bematched for orientation with one of a series of linesarranged like a protractor. The Line Bisection Testrequires the patient to put a cross halfway alongseveral lines. It is sensitive to patients with neglect.The Clock Drawing Test is a measure of visualconstruction (41).4040 Diagram of the Rey–Osterrieth figure.