Descriptive Psychopathology: The Signs and Symptoms of ...

319 Chapter 13: Testing and psychopathology of cognitive dysfunctionAssessing for dementiaDementia is rare in persons under age 65 but the incidence increases substantiallyin persons over age 70. As many as 40% of persons between the ages of 80 and90 years have cognitive impairments in the dementia range. 18 Not all elderlypersons, however, are demented, and many who are cognitively impaired have areversible condition associated with depression or medication toxicity. 19Dementia is diagnosed when the patient exhibits substantial cognitive impairmentwith significant memory difficulties despite minimal deficits in arousal.Once the dementia syndrome is recognized, the next step is to determinethe pattern of the dementing process. Once the pattern is delineated, ideologymay be established.Identifying the dementia syndromePersons who are in the severe stage of a dementing process are not difficult torecognize as their cognitive impairments are substantial and widespread.Although in a state of normal arousal, they will score below 20 and typicallybelow 15 on the MMSE. 20 It is much more difficult, however, to recognize theearly stages of degenerative brain disease and the “pre-clinical” phase of suchconditions.The pre-clinical phase in dementing processes is termed MCI (mild cognitiveimpairment). Once identified, over the next 4years, persons with MCI declinefurther, 10–15% becoming clinically demented each year. 21 Recognizing MCI canlead to early intervention that may delay the progression of the illness, and severalbedside tests are sensitive to MCI and the early stages of dementia.Most dementing processes interfere with working memory, new learning,memory storage, and thinking. The tests below tap those functions and almostall normal persons of all ages perform them within the age-corrected range. 22Early in the MCI stage, the patient may be able to successfully complete thetests but will require extra time as efficiency is reduced. More than expectederrors will occur in persons who previously were high functioning. New learningand recall will be mildly affected. The auditory A test is done first to establishadequate concentration to continue.Digit span: The patient is asked to immediately repeat a series of numbers, thefirst number series forward and the next series backwards. Numbers backwards ismost sensitive to problems with working memory and normal persons under55years of age should recall a minimum of 7 backwards. Normal persons over 70should recall a minimum of 5 backwards. Asking the patient to say the days ofthe week or the months of the year backwards is a less sensitive version of this taskbecause those items are over-learned and are easy to remember forward, whiledigit span offers novel information. 23