Suspected early dementia

I must thank the authors for publishing this article which I have been
waiting for a long time. In my experience, I have noticed that we as
psychiatrists have a very limited knowledge of neuroimaging especially
when it comes to what imaging to ask for and what to look for in imaging.
I strongly think that this article will be of help to fellow psychiatrists
like me.

I believe there is good rational for requesting imaging in patients
who present with cognitive problems, especially patients less than 65
years old. I had the opportunity to see patients with both early onset and
late onset dementia. From my own experience, I can say with confidence
that neuroimaging helped me in clarifying a few diagnosis of complex nature,
and in some cases, incidental findings were picked up which needed
immediate attention from neurosurgeons. I personally find neuroimaging
really useful especially in complex cases where clinical history and
examination don't lead to any conclusions. One example is Frontotemporal
dementia, a devastating neurodegenerative condition which commonly
afflicts people in their middle age, when they are in their prime of life.

The current consensus criteria and neuropsychometric tests are not that
sensitive in picking up the disease; however neuroimaging, particularly
functional neuroimaging (SECT/PET), is more sensitive in picking up this
condition(1). This can be really helpful in clarifying the diagnosis in
its early stages, and therefore help plan interventions and management
strategies more effectively. Similarly, having an idea of MTA (Medial
Temporal lobe Atrophy) can help clinicians to manage patients more
effectively. Apparently, based on current research, MTA is the strongest
predictor for developing dementia(2). The clinicians can therefore put in
place rigorous follow up procedures so as to detect the condition in its
infancy. This is vital as current evidence support health and economic
benefits of early detection and treatment(3). There is also emphasis for
the early detection and diagnosis by government watchdogs like NICE and
Department of health (4,5). Last but not least, neuroimaging can help pick
up treatable causes of cognitive impairment like meningioma and normal
pressure hydrocephalus.

On the other side of the argument, I strongly believe that nothing can
substitute a good history taking and clinical examination. This is quite
important, essentially in differentiating different types of dementia. It
is quite easy to fall into the fallacy of diagnosing patients with
vascular dementia based on imaging findings of small vessel disease, which
actually could be age related and non-specific, as mentioned in this
paper.

In summary, I believe neuroimaging is a vital investigation in
patients with cognitive impairment. It is useful in picking up the
treatable causes of cognitive impairment and helps clarify diagnosis which
at times is not very clear from clinical history and examination. I think
we should follow NICE guidelines and request a neuroimaging at least a CT
if not MRI on every of our patient with memory related complaints.

1. Mario F. Mendez, Jill S. Shapira, Aaron McMurtray, Eliot Licht,
Bruce L. Miller. Accracy of the Clinical Evaluation for Frontotemporal
Dementia. Arch Neurol. 2007; 64(6):830-835.

2. Geroldi C, Rossi R, Calvagna C, Testa C, Bresciani L, Binetti G,
Zanetti O,Frisoni GB. Medial temporal atrophy but not memory deficit
predicts progression
to dementia in patients with mild cognitive impairment. J Neurol Neurosurg
Psychiatry. 2006 Nov;77(11):1219-22.

3. Relkin N. Screening and early diagnosis of dementia. Am J Manag
Care. 2000 Dec.

4. Living well with dementia: A National Dementia Strategy.

5. National Institute for Health and Clinical Excellence (2006)
Dementia: supporting people with dementia and their carers in health and
social care. NICE-SCIE clinical guideline 42.