Intended for healthcare professionals

Research

Self administered cognitive screening test (TYM) for detection of Alzheimer’s disease: cross sectional study

BMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b2030 (Published 10 June 2009) Cite this as: BMJ 2009;338:b2030

Authors' reply

There has been much interest in the publication of the new cognitive
test “Test Your Memory (TYM)”.

We have received many positive comments but there has been some
misinterpretation of our findings. The TYM test is intended to be self-
administered by the patient and this is a central feature – as it allows
testing of 10 cognitive skills in minimal operator time. The TYM test
needs to be overseen and interpreted by a health professional. The test is
therefore self-administered but not for self diagnosis. It is hard to
choose an alternative title which clarifies this without being too long.
As a result of the publicity concerning self testing we have delayed the
launch of the website tymtest.com until we can ensure easy access for
professionals whilst discouraging self testing.

The TYM test has been validated in a single study in a single
population who have presented with cognitive problems. It shows great
promise as a screening tool in this setting. Some of the replies highlight
problems that would occur with indiscriminate screening of asymptomatic
patients, where the number of false positives would cause many problems.
We would agree that such testing is not appropriate. A low TYM score
suggests the need to look for a cause (which can be as simple as leaving
spectacles at home), it does not mean the patient has Alzheimer’s disease.
We agree that the TYM test needs to be validated in other populations.
Longitudinal data is crucial and is being collected.

The TYM test is not a diagnostic test. The diagnosis of Alzheimer’s
disease needs a proper clinical assessment from a trained professional.
The TYM test is an aid in this process but not a replacement for it. Human
beings and brain diseases are inherently variable and it is unlikely that
there will ever be a quick memory test which would allow an untrained
person to safely diagnose Alzheimer’s disease or distinguish Alzheimer’s
disease from other forms of degenerative or vascular dementia. An
experienced clinician may recognize a pattern of scoring on the TYM which
suggests Alzheimer’s disease or semantic dementia in many patients.

The TYM test can be completed quickly by most patients and be
supervised by an individual who has received minimal training. This is not
the same as saying that it should be done in a busy room or casually. The
patient should give verbal consent, be sat in a quiet area away from other
patients, clocks and newspapers and the supervisor will need to help if
necessary. In many of the clinics where we have used the TYM, certain
nurses or receptionists have proven very competent at supervising the test
and there has been a suitable area. If this is not possible or there is
more time then we supervise the test ourselves. We would agree that there
are clear advantages in the clinician supervising the test. Whilst this
will take up 5 minutes of the clinician’s time watching the patient often
yields more information and we usually find it possible to do some other
tasks such as reading notes or filling forms at the same time.

The TYM test as published is culturally biased. A major advantage of
the TYM test is that it can be translated and adapted for many other
cultures and languages without changing the basic structure. Over a dozen
different language/cultural versions are under preparation; these
different versions of the TYM test will also need to be validated. We hope
to place these on the website tymtest.com. We are also working on versions
of the TYM suitable for patients with visual impairment and physical
disabilities.

In answer to more specific points, we include a wide age range of
controls because many younger patients have cognitive complaints as a
result of epilepsy, multiple sclerosis and other conditions and we believe
the TYM test may be useful in these patients. The average TYM scores of
controls are remarkably stable but do fall off after the age of 70 years
as do most similar tests. There were no significant differences between
older and younger patients with Alzheimer’s disease.

The use of occasional prompts is to try to make as clear as possible
to patients the answer required – so that failure to complete a space
properly is because the task couldn’t be done not that the patient was
unsure of what was required.

We are well aware of the ethical debate around early diagnosis of
Alzheimer’s disease and share many of the concerns of your correspondents.
It is vital, in our opinion, that progress is made towards early diagnosis
for several reasons; one important reason is that if a treatment which
halts Alzheimer’s disease becomes available, we need a test to identify
those likely to benefit.

Competing interests:
None declared

Competing interests: No competing interests

09 July 2009
Jeremy Brown
Consultant Neurologist
George Pengas, Kate Dawson, Lucy A Brown, Philip Clatworthy
Department of Neurology, Addenbrooke’s Hospital, Cambridge CB2 2QQ