Mohammed T. Abou-Saleh

298 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYmemory in the patient. In contrast, in patients with depression, ifcognitive symptoms are reported, it is usually by the patient. Theyalso stated that the duration of the presentation could be helpfulin clarifying the diagnosis. Depression is typically of shorterduration than dementia and usually with a more well-definedonset. The authors also recommend a review of personal or familyhistory for depression, and a review of family history fordementia.SCREENING INSTRUMENTSThe use of various ‘‘bedside’’ screening instruments has beenproposed as a way to clarify the diagnoses of dementia anddepression. Common instruments used in the diagnosis ofdepression include the Hamilton Rating Scale for Depression(HAM-D), the Beck Depression Inventory (BDI), and theMontgomery–Asberg Depression Rating Scale (MADRS). Ingeneral, many authors have found that general depressionscreening instruments are less helpful in the diagnosis ofdepression in the elderly than in the general adult population.Reasons for this age disparity include decreased specificity, due tooverlap of many depression symptoms with other commongeriatric presentations, including dementia and general medicalillnesses. It is also believed that the sensitivity is decreased, as notall of the classic symptoms of depression are as common in thegeriatric population as in the general adult population.A number of depression screening tools specifically designed tobe used in geriatric or demented patients have been developed.Among the more commonly used instruments are the GeriatricDepression Scale (GDS), Alzheimer’s Disease Assessment Scale(ADAS) and the Cornell Scale for Depression in Dementia (CS).The ADAS relies on observation of the patients and thus avoidsmany of the difficulties inherent in interviewing a cognitivelyimpaired individual 11 . The CS combines interviews with thepatient and caregivers, focusing on behavior during the weekpreceding the interview, thus taking advantage of availablecollateral information that many other scales ignore 11,12 .The most commonly used dementia screening tool is the Mini-Mental State Examination (MMSE). The MMSE was developedby Folstein et al. in 1975 13 . Since that time, it has become the mostwidely used examination for rapidly assessing the cognitive statusof the elderly 14 . This short test covers a broad range of cognitivedomains, including orientation, registration, attention and recall,calculation, language, and constructional ability 15 . Age- andeducation-specific reference values have been developed to helpguide the clinician in the use of the MMSE in variouspopulations 14 .Other tests that have been developed to screen for cognitiveimpairment in the elderly include the Blessed Dementia RatingScale and the Short Portable Mental Status Questionnaire(SPMSQ). A quick and simple-to-administer test, the clockdrawingtest, has been shown in numerous studies to be a goodscreening test for dementia 16 . Numerous methods have beendeveloped to score the clock-drawing test, ranging from complex20-point scales to more simple ordinal scales.Watson et al. 17 , developed a scoring system that is based on aseven-point scale. With this method, the patient is instructed todraw numbers within a pre-drawn circle to make the face of aclock. After completion, the clock face is divided into quadrantsand the number of digits in each quadrant is counted. An errorscore of one is assigned for each of the first three quadrantscontaining any erroneous number of digits and an error score offour is assigned for the fourth quadrant if it contains an erroneousnumber of digits. A score of 4 or greater has been shown to have asensitivity of 87% and a specificity of 82% in screening fordementia 16 .Kafonek et al. 18 conducted a study to determine the sensitivityand specificity of the MMSE in detecting dementia and theGeriatric Depression Scale (GDS) for detecting depression in anacademic center-affiliated nursing home population. They foundthat, in screening for dementia, the sensitivity of the MMSE was81% and the specificity was 83% when using a cut-off score of 24/30. The GDS was found to be less sensitive and less specific inscreening for depression, with a sensitivity of 47% and aspecificity of 75%. Thus, while such screening tools can provideuseful additional information, they should be taken into considerationas part of the overall clinical picture and not used as thesole basis for making or excluding a diagnosis.NEUROPSYCHOLOGICAL ASSESSMENTFormal neuropsychological testing is often employed to helpdiagnose dementia and depression in the geriatric population.Neuropsychologists are able to administer a full battery of teststhat have at least three distinct functions in the assessment ofgeriatric patients 19 . The first goal of neuropsychological testing isto aid with differential diagnoses between normal aging,psychiatric disorders and neurodegenerative/dementing disorders.A second common use of formal testing is to establish a baselinefrom which changes can be tracked over time. This can help indetermining the response to treatment for depression or dementia,as well as to systematically follow the progression of dementingdisorders. The final common use of neuropsychological testing isto delineate the strengths and weaknesses of a particular patient,to help make clinical recommendations for treatment, dailyactivities and planning for the future.In an exhaustive review of the neuropsychological testingliterature dealing with the differential diagnosis of majorprogressive dementias and depression, Rosenstein 20 summarizedthe major test variables that neuropsychologists have foundhelpful in distinguishing depression from various dementingdisorders. In general, she reports that depressed patients tend todemonstrate normal to slightly reduced attention, memory,visuospatial functions, language, executive function, reasoningand sensory-motor function, with a negative or empty responsestyle and inconsistent performances (even within the samedomain). In contrast, patients with AD tend to demonstratemore significant impairment in memory, verbal fluency andexecutive function (in particular, poor awareness of deficits), witha higher prevalence of false-positive responses and intrusions.Obviously, the milder the dementia at the time of testing, themilder will be the above-mentioned deficits. However, even milddeficits will be more accurately detected on formal neuropsychologicaltesting than with the usual clinical assessment, or withscreening tests such as the MMSE. This increased sensitivity is oneof the strengths of formal neuropsychological testing. As part of aprospective epidemiological study of dementia, Jacobs et al. 21administered a comprehensive neuropsychological test battery toa group of initially non-demented older adults, in order toexamine the association between baseline scores and subsequentdevelopment of dementia. The results of the study indicate that,even in the preclinical phase of AD, deficits can be found in areasof word-finding ability, abstract reasoning and memory.MacKnight et al. 22 , in their paper examining the factorsassociated with inconsistent diagnosis of dementia betweenphysicians and neuropsychologists, concluded that the twodisciplines have complementary strengths. The neuropsychologisthas superior skills in identifying early cognitive loss, while thephysician’s expertise arises from a greater ability to assess theimpact of the impairment on the patient’s ability to function.Thus, if available to the clinician, formal neuropsychologicaltesting can provide very helpful and complementary information.