Andrew Kertesz, MD, FRCP(C), Director of Cognitive Neurology, St. Joseph’s Health Center, University of Western Ontario, London, ON.
David Munoz, MD, FRCP(C), Department of Pathology, St. Michael’s Hospital, University of Toronto, Toronto, ON.

Frontotemporal dementia (FTD or Pick’s disease) is a relatively common but underdiagnosed form of presenile dementia. Estimated prevalence is 20% of dementias and 50% of dementia in patients under age 65. Common presentations are disinhibition with indifference; progressive aphasia; semantic dementia; unexplained falls, vertical gaze palsy, and dysarthria; and dementia with motor neuron disease. Neuroimaging is essential to exclude a slow tumour. Tau mutations are found in some families. Atypical neuroleptics and antidepressants can effectively treat some of the characteristics of FTD.

Key words: frontotemporal dementia, Pick’s disease, primary progressive aphasia, corticobasal degeneration, progressive supranuclear palsy.

Céline Chayer MD, FRCPC, Behavioural Neurology, Hôpital Maisonneuve Rosemont, Montreal, PQ.

Introduction
The prevalence of dementia in Canada has been estimated at 8%, after the age of 65 years.¹ Alzheimer disease (AD) accounts for approximately 60% of cases, while other conditions accounting for the remaining 40% include, among others, vascular dementia, dementia with Lewy bodies (DLB) and frontotemporal lobar degeneration (FTLD). Differences in prognosis and symptomatic treatment, as well as eventually disease-modifying therapy underline the importance of the differential diagnosis of dementia. The use of clinical criteria for diagnosis of degenerative and vascular dementias can increase the level of clinical diagnosis accuracy² and should, therefore, be known by physicians dealing with dementia. Advances in the understanding of FTLD have been made over the past 15 years. We will review the clinical manifestations of FTLD and highlight the differences with AD.

Pick's disease, fronto-temporal lobar degeneration and Pick complex
In 1892, Arnold Pick described patients with predominant language impairment in whom focal atrophy of the frontal and temporal lobes was found.³ Later, Alois Alzheimer described, in Pick's original patients, ballooned cortical neurons containing cytoplasmic inclusions that were subsequently called Pick bodies. Pick's disease became synonymous with frontotemporal dementia.