Lewy body disease is of interest to a wide range of medical specialties (neurology, psychiatry, geriatrics) and the combined neurosciences of Alzheimer’s and Parkinson's disease. The original Consortium report which this paper updates (McKeith et al, NEUROLOGY 47 (5): 1113-1124, NOV 1996) has itself been cited almost 1,500 times.

“People with DLB are doubly disabled compared with Alzheimer’s disease because they have motor, autonomic, and psychiatric disability as well as cognitive impairments.”

This is the third in a series of papers which describe pathological and clinical methods for the diagnosis and classification of dementia with Lewy bodies (DLB) and commentate on our current knowledge about underlying mechanisms. I suppose the first paper reported the "discovery" of DLB as the commonest type of degenerative dementia after Alzheimer’s.

Since then we have evolved methodologies to detect and report neuropathological lesions and to quantify clinical phenomena such as fluctuating cognitive impairment. This latest paper revises some of our early recommendations and for the first time offers treatment guidelines.

Accurate diagnosis and treatment of DLB is important because the use of antipsychotic drugs is associated with a two- to three-fold increased mortality (they should be avoided) and good treatment responses may be seen with cholinesterase inhibitors and some antiparkinsonians.

Clinicians often lack experience and confidence in detecting and managing DLB, which is a common disorder affecting between 15-20% of all dementia sufferers. Career organizations are recognizing the unmet needs of DLB patients and support charities have been set up in the USA and UK to start addressing these concerns.

I started as a psychiatrist doing receptor binding on the postmortem human brain in affective disorder. As a consequence I became involved in clinically assessing cases for the Newcastle Brain Bank where Tomlinson, Blessed, and Roth had earlier described Alzheimer’s as the commonest cause of dementia in old age. I came across cases of what we then called "senile dementia of the Lewy body type" (SDLT) and started doing clinicopathological correlative studies.

The Consortium came together to resolve differences between international research groups who were all working on the same group of patients and competing rather than collaborating. The biggest obstacle has been keeping the story straight and bringing movement disorder and dementia specialists together under one roof.

We have just published a large multi-center study of in-vivo dopamine transporter imaging as a diagnostic test for DLB (McKeith et al, Lancet Neurol. 6(4):305-13, 2007 ) which is the first dementia subtype specific biomarker that has been validated for clinical use. Now we can diagnose DLB accurately on a large scale and are ready to do randomized trials—all we need are the right agents!

Immunotherapy against amyloid and/or alpha-synuclein appear to be the front-runners, but we have to wait until the transgenic mice and protein-chemist guys come up with something to test in humans.

The scale and cost of the problem are large. People with DLB are doubly disabled compared with Alzheimer’s disease because they have motor, autonomic, and psychiatric disability as well as cognitive impairments.

Lewy body disease is no respecter of our traditional medical specialty boundaries and to understand its full range of effects requires us to take a much more interdisciplinary approach which may reflect how our specialties will evolve as we understand diseases more in terms of underlying mechanisms rather than how they present in the clinic.