Mohammed T. Abou-Saleh

Principles and Practice of Geriatric Psychiatry.Editors: Professor John R. M. Copeland, Dr Mohammed T. Abou-Saleh and Professor Dan G. BlazerCopyright & 2002 John Wiley & Sons LtdPrint ISBN 0-471-98197-4 Online ISBN 0-470-84641-037Early DetectionScott HendersonCentre for Mental Health Research, The Australian National University,Canberra ACT 0200, AustraliaIS EARLY DETECTION IMPORTANT?Why try to detect dementia early in its course? Since the advent oftechnologies for the early detection of disease, it has becomeimportant to ask whether early recognition is worthwhile, and forwhom. Can it be shown that a lower level of morbidity is achievedin a population that has been screened, compared to others thatwere not screened? Is the quality of life of cases improved by theirearly diagnosis; or could early detection of dementia ‘‘seriouslydamage your health’’, as has been found for other disorders 1 ? Fora start, evaluation of the early detection of dementia would haveto take note of the 10 principles of screening, as listed by Wilsonand Jungner 2 . These include the requirement that there be anaccepted form of treatment for persons once detected, thatfacilities for diagnosis and treatment be available to thepopulation being screened, and that a suitable test be availablefor detecting the disease in its early stages. Clearly, screening forearly dementia is a procedure where none of these requirementshas yet been met.Cooper and Bickel 3 have nevertheless indicated some of theadvantages that screening or early detection could bring. Theypoint out, first, that the biggest gap between those receivingspecialist psychiatric care and the total volume of morbidity ina general population is amongst its elderly; and that mentaldisorders in this age group are probably under-recognized bygeneral physicians. Second, a proportion of cases detected asdementia have reversible conditions such as depressive disorder,normal pressure hydrocephalus, metabolic disorders or braintumours. Third, early detection can be a preliminary not tocurative treatment but ‘‘to intervention aimed at reducingdisability and postponing the need for institutional care’’. Suchintervention is well placed with the general practitioner and theperson’s family. It can then be added that, for the generalpractitioner, the advantages of early detection are appreciable:the possible causes of the cognitive or behavioural deteriorationmay need to be pursued. Where co-morbidity emerges, as itcommonly will, the physician’s awareness that dementia ispresent will prove useful in assessment and continuing management;and the presence of dementia may influence the choice ofmedication.There is one further reason for early detection, although this isnot to the individual patient’s immediate benefit. For research ondementia, it is of great importance to know about the earliestsymptoms and signs before these become buried by the dementiaitself. Without this information, and without knowing the clinicalcourse of mild cases, it may not be possible to improve thespecificity of screening, and to distinguish between mild cognitivedecline and normal ageing 4 . For population-based research, wheresome early cases will inevitably be identified, Brayne et al. 5recommend that a two-stage design should ideally be used,along with a third assessment that serves as a gold standard:evidence of progression of the dementia; or neuropathology atpost mortem.HOW IS EARLY DETECTION ACHIEVED?Early detection will usually mean the dementia is of only mildseverity. It is an advantage, therefore, that the diagnosticcriteria for mild dementia have been specified in both ICD-10 6and DSM-IV 7 . In ICD-10, the declining memory and informationprocessing causes impaired performance in daily living,but not to a degree that is incompatible with independentliving. Explicit criteria are given for the diagnosis of milddementia.Early detection can be carried out at three levels: in thecommunity, in primary care settings, and in hospitals. In thecommunity, screening is conducted only as part of researchstudies, and has not yet been used in a way similar to other routinescreening for disease. In primary care, early detection is at presentconducted informally and is based largely on the initiative andclinical skill of the practitioner. It is not clear what mostcommonly prompts the physician into considering a diagnosisof early dementia. Rarely it would be, say, all persons aged 70years and over consulting in a given period, but rather those whoprompt the physician’s concern. Commonly, it is the patient’sfamily who have first detected a deterioration in cognition orbehaviour. The present consensus is that, in the absence of someindication, efforts to detect early dementia in general practice areunwarranted. But there may be a place for routinely obtaining abase-line measure of cognitive performance against whichsubsequent assessments can be placed. There is as yet no placefor annual repetition of the assessment.Tests for Early Detection of DementiaIn hospitals and clinics, the realities of clinical practice are thatearly detection of dementia is achieved in one of two ways. Inthe more common style, the clinician obtains a history fromothers that a decline in cognitive performance and/or behaviourhas taken place. To this is added some non-systematic cognitiveassessment of the patient, leading to a conclusion on whetheror not early dementia is present. Clearly, other clinical features,Principles and Practice of Geriatric Psychiatry, 2nd edn. Edited by J. R. M. Copeland, M. T. Abou-Saleh and D. G. Blazer&2002 John Wiley & Sons, Ltd