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 0-470-84641-0146 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYPsychogeriatric Assessment ScalesA. F. JormCentre for Mental Health Research, The Australian National University, Canberra, AustraliaThe Psychogeriatric Assessment Scales (PAS) aim to assess theclinical changes of dementia and depression using a set ofcontinuous scales 1 . The PAS consists of two parts, an interviewwith the patient and an interview with an informant who knowsthe patient well. The purpose of interviewing both the patient andan informant is to acquire different perspectives on the patient’simpairments. The PAS consists of six scales, three derived fromthe interview with the patient and three from the interview withthe informant. The content of these scales is as follows:Patient Interview:. Cognitive impairment. This consists of brief tests of cognitivefunctioning and is sensitive to dementia. It correlates highlywith the Mini-Mental State Examination.. Depression. This asks about common symptoms of depression.It correlates highly with the Goldberg Anxiety and DepressionScales.. Stroke. This scale asks about symptoms of cerebrovasculardisease and is useful in differentiating Alzheimer’s dementiafrom vascular dementia. It correlates highly with theHachinski Ischemic Score.Informant Interview:. Cognitive decline. This scale asks questions about everydaycognitive functioning and is sensitive to dementia. It correlateshighly with the Informant Questionnaire on Cognitive Declinein the Elderly (IQCODE).. Behaviour change. The questions in this scale cover aspects ofbehaviour that could cause interpersonal difficulties and aresensitive to both depression and dementia.. Stroke. The scale involves the same questions as asked ofthe patient, but provides an independent source ofinformation.Each scale yields a score along a continuum, and norms areavailable to show how rare a given score is in the population. Thescores can be plotted as a graph to give a readily interpretablesummary of the patient’s pattern of impairments.The PAS scales were derived from a principal component andlatent trait analysis of items that were designed to cover the ICD-10 and DSM-III-R diagnostic criteria for dementia and depression1 . Items for the PAS scales were selected to have steep slopes(i.e. to be highly discriminating items) and to have a range ofthresholds (i.e. to cover a range of severity).Validity has been assessed against clinical diagnoses ofdementia and depression using receiver operating characteristic(ROC) analysis 1,2 . The Cognitive Impairment and CognitiveDecline scales perform well as screening tests for dementia,while the Depression scale performs well as a screening test fordepression. The Behaviour Change scale is non-specific, beingaffected by both dementia and depression. The Stroke scalesperform well at discriminating vascular from non-vascular(mainly Alzheimer’s) types of dementia.The PAS materials and User’s Guide 3 can be downloaded freefrom the Web at http://www.mhri.edu.au/pas/. For people whodo not have Internet access, printed copies are available bywriting to: PAS Project, Centre for Mental Health Research,Australian National University, Canberra 0200, Australia. ThePAS is available in a number of other languages, includingFrench, German, Italian, Chinese and Korean. For details ontheir availability, write to the above address.REFERENCES1. Jorm AF, Mackinnon AJ, Henderson AS et al. The PsychogeriatricAssessment Scales: a multi-dimensional alternative to categoricaldiagnoses of dementia and depression in the elderly. Psychol Med1995; 25: 447–60.2. Jorm AF, Mackinnon AJ, Christensen H et al. The PsychogeriatricAssessment Scales (PAS): further data on psychometric properties andvalidity from a longitudinal study of the elderly. Int J Geriat Psychiat1997; 12: 93–100.3. Jorm A, Mackinnon A. Psychogeriatric Assessment Scales: User’sGuide and Materials, 2nd edn., Canberra: ANUTECH, 1995.