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 0-470-84641-051bFrontotemporal Dementia (Pick’s Disease)John R. HodgesMRC Cognition and Brain Sciences Unit, Cambridge, UK‘‘Frontotemporal dementia’’ is the term currently preferred todescribe patients with focal cortical atrophy involving the frontaland/or temporal lobes. Pathologically, such patients show severeneuronal loss, spongiosis and gliosis, and in a minority of casesclassic argyrophilic, tau-positive intraneuronal inclusions arepresent (Pick bodies). The hallmark changes of Alzheimer’sdisease are virtually always absent 1 .One of the most exciting developments in the past decade hasbeen the discovery of mutations in the tau gene on Chromosome17 in some families with dominantly inherited FTD 2 , although itshould be stressed that most cases are sporadic. Clinically, FTDpatients present with one of three major syndromes, which reflectthe initial locus of pathology: dementia of frontal type, semanticdementia and progressive non-fluent aphasia 3 . It should be notedthat each of these syndromes can be associated with motorneurone disease and a full neurological evaluation should also beincluded, especially in rapidly progressive cases and if bulbarsymptoms develop 4 .Patients with FTD present below the age of 65 and there is anequal sex distribution. Although rare, FTD is the secondcommonest cause of dementia in the presenium (after Alzheimer’sdisease) 5 . In Cambridge we have studied approximately 100 caseswith FTD; the rarest syndrome is non-fluent progressive aphasia,the other two account for approximately 40% of cases each. Theaverage survival from diagnosis is, on average, 10 years. In ourexperience, patients with the frontal form of the disease progressat the slowest rate, semantic dementia cases have a more rapidcourse and those with motor neurone disease-associated FTDrarely survive more than 2 years.A major advance in the area has been the development of a semistructuredcarer interview, the Neuropsychiatric Inventory, whichappears to be able to differentiate patients with FTD and AD 8 .Neuropsychological FindingsSome patients show clear-cut cognitive deficits at presentation butmost traditional ‘‘frontal executive’’ tasks are sensitive to dorsolateral,rather than orbitobasal frontal, dysfunction; among themost useful are the Wisconsin Card Sorting Test and verbalfluency (i.e. the generation of words beginning with a given letterof the alphabet). Recently, quantifiable tasks involving decisionmakingand risk-taking and better able to detect orbitobasalfrontal function have been developed 9 .Memory is relatively spared: orientation and recall of personalevents is good but performance of anterograde memory tests ismore variable, and patients tend to do poorly on recall (asopposed to recognition)-based tasks. A reduction in spontaneousconversation is common, but patients with DFT perform well ontests involving picture naming and other semantically-based tasks.Visuo-spatial abilities are strikingly preserved, particularly whenthe organization aspects are minimized: the Rey figure test is oftencopied poorly due to impulsiveness and poor strategy 10 .Simple cognitive screening tests, such as the Mini-Mental StateExamination (MMSE), are unreliable for the detection andmonitoring of patients with DFT, who frequently performnormally even when requiring nursing home care 11 .DEMENTIA OF FRONTAL TYPE (DFT)(FRONTAL VARIANT FTD)The onset of symptoms is insidious and insight is lacking.Relatives complain of a change in personality and behaviour:disinhibition, poor impulse control, antisocial behaviour, stereotypicalfeatures (e.g. insisting on eating the same food at exactlythe same time daily, cleaning the house in precisely the same orderor the use of a repetitive catchphrase) and a change in appetiteand food preference towards sweet food are the features that bestdiscriminate FTD from Alzheimer’s disease. They reflect the earlyinvolvement of the orbitobasal frontal cortex 6,7 . Apathy is alsovery common but non-specific. Deficits in planning, organizationand other aspects of executive function are universal as the diseaseprogresses to involve the dorsolateral prefrontal cortex. Majordepression and psychosis are rare.SEMANTIC DEMENTIA (TEMPORAL LOBEVARIANT FTD)Patients with this variant of FTD present with a progressive fluentaphasia but the underlying cognitive deficit is a breakdown insemantic memory 3,12 . Semantic memory is the term applied to thecomponent of long-term memory which contains the permanentrepresentation of things in the world, including objects, words andpeople. It is the database which gives meaning to our sensoryexperiences.Patients complain of ‘‘loss of memory for words’’. Althoughaware of their shrinking expressive vocabulary, patients arestrangely oblivious to their impaired comprehension. Since thegrammatical and phonological structure of language remainsintact, the changes are relatively subtle, at least in the early stages.Patients with predominant right-sided atrophy may present withdifficulty recognizing faces (prosopagnosia), at first affecting lesscommonly encountered people but with time severe prosopagnosiaPrinciples 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