26 May 2022

The early signs of dementia: part 2

General Practice Neurology

A leading expert answers GP questions about the early signs of dementia.


Professor Michael Saling presents an approach to the assessment of memory complaints to help GPs differentiate true early dementia from the worried well. Early referral to a neuropsychologist is important to the patient and the family, as obtaining the correct diagnosis is critical. This is part two of this series.

Practice points

  • In alcoholic brain damage, drinking has to be extremely heavy to cause a Wernicke–Korsakoff syndrome. The majority of heavy drinkers are really extreme social drinkers and the frontal lobe shrinkage reverses if they become abstinent. Thiamine is important.
  • Hippocampal sclerosis dementia is quite a late-onset thing and there can be some Alzheimer’s pathology and Lewy body dementia pathology. There is a prominent hippocampal sclerosis and some patients have had a temporal lobe seizure at some point in their lives.
  • There is no disease-modifying agent apart from aducanumab, which is not particularly effective. The main thing is the symptomatic treatment for patients with dementia.
  • Organisations such as Alzheimer’s Australia have all the supports and can direct patients to where they need to go.

Professor Michael Saling (MS)

My name is Michael Saling and I am a professor of neuro-psychology at Melbourne University. I am also a clinical neuropsychologist based at the Austin Hospital, Melbourne. I have directed the department and been running a cognitive disorders clinic for quite a number of years. I have recently retired and am continuing as a professorial Fellow.

Patients with early-stage dementia are actually quite a big component of my clinical life and in many cases they have quite complex and unusual dementias. The differential diagnosis is one of the main things we are engaged in that can assist others.

Dr David Lim (DL):

You’ve given us some very good tools and the ability to judge whom we should refer for formal testing. However, we’ve just mentioned a group of people who have well-formed hallucinations who will completely reject your desire to help them in many cases. What do we do as GPs, do we schedule them? What do we do with people who really honestly believe that they’re seeing people coming to the house, but who are refusing help?

MS:

There can be a psychosis, but if there is a background of an extra pyramidal disorder, such as Parkinsonism, together with that, then the general referral pathway tends to be from GP to neurologist, just to make sure that the Parkinsonism isn’t idiopathic Parkinson’s disease.

We have a very big GP referral base, but referrals can also be made through a neurologist, a geriatrician or a psychiatrist. If there is some sort of movement disorder, I would suggest the neurological referral in the first instance.

If the specialist then feels that this is not idiopathic Parkinson’s disease, that patient might be referred to us. We see quite a number of cases with Lewy body dementia and this is said to be the second-most-common dementia. I am not entirely sure about that, but it’s not uncommon.

DL:

I’m going to now put forward to you a scenario. You have some patients come through and the GP has decided that there is significant cause for concern and, as you said, this will result in a referral to a neurologist to exclude true neurological disorders. Eventually they end up in your hands or perhaps might be referred straight to you. Tell us what happens when they see you, how you assess them and what can we do to help.

ML:

We spend quite a long time taking a history. We have the luxury of time, and GPs don’t. We can spend quite a bit of time talking to the significant others and understanding what they have observed. We do a formal examination now. Unfortunately, neuro-psychology has a reputation of spending three or four hours on a lengthy assessment that doesn’t say much.

We don’t do that. We do a targeted assessment, depending on what we think the presentation is consistent with. All in all, we will have spent, maybe an hour with the patient, or maybe a tad over an hour, and then we see them again. When we have looked at the findings and talked to them about the possibilities, we might make a recommendation for an 18F-FDG PET scan.

If for some reason that’s already been done, we might suggest acetylcholinesterase inhibitors if the patient has early Alzheimer’s disease, because they do work well. It’s a fairly lengthy engagement with each patient, but that’s essentially the process.

DL:

This presentation of dementia is not a diagnosis that is an easy one to make, especially for a GP. You just want to get it right, don’t you?

MS:

Yes, absolutely, and it does require a neuro-psychological examination, There are sets of diagnostic criteria that exist. Of course, in memory clinics there has to be a neuro-psychological investigation. Whatever concerns the GP might have, we’re always pleased to see the patient, because early detection is the thing we concentrate most on. That’s what most of my research on dementia has been about.  So even if you’re just not sure, we’d be more than happy to see the patient, as would all neuropsychologists, because the earlier the better.

DL:

Let’s just say I have a patient who has a language issue, or something that might make it problematic speaking with you. What do we do then? Do we still make the referral and hope that something can be assessed?

MS:

Oh yes, definitely. Aphasiology is a very big part of what we do, and it comes into play a lot in patients with an acute stroke. It has also become more and more important in Alzheimer’s disease. It’s interesting to note that Alzheimer’s original index case was an early-onset case involving a language problem. So his first case was, in fact, not a typical onset as we know it today. If there are word-finding difficulties in somebody between 45 and 60 years of age, there should be concern. I think that would be worth a referral.

DL:

What should GPs do in terms of investigations before referring to neurologists and to you? Should we do, for example, a syphilis screen or investigate for subdural bleeds, thyroid issues?

MS:

That used to be called the dementia screen. If it were normal, we were then free to diagnose Alzheimer’s disease or another dementia type, as this is actually a diagnosis by exclusion. All of those things are worthwhile, CT scans, blood tests and serology, depending on what your concerns are. Other possible causes may be excluded because there are a few things that do mimic Alzheimer’s disease.

DL:

How does heavy alcohol intake affect our assessment and concerns about Alzheimer’s disease or an alcohol-related disorder?

MS:

If there is an early-stage Alzheimer’s pathology developing, alcohol won’t help. It will probably cause a more severe and earlier presentation symptomatically. In terms of alcoholic brain damage, drinking has to be extremely heavy to cause a Wernicke–Korsakoff syndrome. I think the majority of heavy drinkers that we see are really extreme social drinkers and they can have a bit of frontal lobe shrinkage, but if they become abstinent this can actually reverse. However, if they get actual Wernicke–Korsakoff pathology in the brain, this is, of course, irreversible. Thiamine is always the important issue. I don’t think we’ve seen a case of Wernicke–Korsakoff syndrome for a very, very long time. I think GPs know the nutritional primary care work to do. We’re not a sort of a specific site for that condition, but we do see, you know, the more extreme end of social drinking.

DL:

How accessible to GPs are clinic neuropsychologists? How soon can they see a patient if we refer?

MS:

In my day, as a private practice, it was something that could have been done pretty soon. At a hospital level, we do have a fairly long waiting list, but we triage that very frequently. If you are worried about a patient, we will certainly organise to see them earlier, or alternatively, we can have a telehealth interaction with them to begin with and see where to go from there. If there is concern about them, we will do everything we can to see them in a timely fashion, at the hospital level.

DL:

At a practical level, helping GPs develop, if you like, a priority of concern: would this be safety, security, and at what severity? How would we work to push the patient’s case up the top of the list? What would be the red flags?

MS:

I think the red flags really are the things that I have mentioned, actually. I think with Alzheimer’s disease, the red flag issue is just early symptomatology. Early detection is just so vitally important now. I mean that these patients aren’t classically urgent cases, medically, I’m sure you see very much more urgent issues than that, but from our point of view, we would prioritise them. So urgency for us is a little different to what it would be in primary care or emergency care.

DL:

We are subject to pressure from significant others as well…

MS:

We certainly do our very best to see them in a timely fashion. Our department makes early contact with them, has a chat and makes sure that they understand they’re going to be cared for.

DL:

What sort of support for the family and the significant others (after their loved ones have just been given a diagnosis) have you all developed through your research?

MS:

In terms of family support, it’s the organisations such as Alzheimer’s Australia that have all of that at their fingertips. We are primarily diagnosticians, but we do talk to the family on the days we see them to settle them down psychologically as much as we can. However, very often, once we detect a memory impairment in a patient whose family has become concerned, there is definitely an initial sense of relief. Somebody has noticed the issue that’s been worrying them all.

That goes a long way in the short term, but it is in the long term that things start becoming very difficult; in the early stage, things aren’t that tough. When things become very difficult, then it will be those organisations that have all the supports and can direct them where they need to go. We do meet with families to talk things through with them, but it’s difficult.

DL:

It’s a very hard diagnosis, isn’t it? To watch the person you love slowly fade away to be somebody else.

MS:

Yes. Oh, Yes. The endless funeral, as it sometimes called.

DL:

How long are they living these days, from time of diagnosis?

MS:

It’s quite variable, actually. The survival time was said to be about eight years but we are seeing patients survive longer than that. It has always been very variable; some patients go on for an incredibly long time.

Then, of course, there are slowly progressive forms that closely resemble Alzheimer’s disease. Hippocampal sclerosis dementia is one of those. It tends to surface in the group above the age of 80, the “oldest of oldies” as they call it. That’s quite a late-onset thing and there can be some Alzheimer’s pathology and on post-mortem there. There can even be Lewy body dementia pathology. There is a prominent hippocampal sclerosis and some of them have had a temporal lobe seizure at some point in their lives, but they’re not patients who present with temporal lobe epilepsy in the normal run of things.

We tend to see them in our temporal lobe epilepsy program, within which I’ve done a lot of consulting … one of my major areas in years gone by. That was a surgical-treatment program, headed by Sam Burke at the time. We would see them in their 30s for workups at that stage. These older patients with hippocampal sclerosis dementia have never gone that route. They obviously hadn’t had any classical temporal lobe epilepsy, but they have often had one or two seizures somewhere along the line.

So that’s not an Alzheimer’s disease predominant condition and it is super-slowly progressive, really slowly. We’ve seen them year after year with very little change, until there is change, and then …

DL:

I suspect they would be fairly old by then. Now you have taken me through a lot of good information and practical steps. I’m just wondering if there have been some important messages that I might have missed.

MS:

One of the things that we are very often greeted with is people that have noticed that in the media that there are cures for Alzheimer’s disease, and there are blood tests that detect it … you know, there is obviously no understanding of how that applies. That’s quite a frequent conversation. I had one such conversation this very morning. The blood tests, of course, are important for preclinical cases. If there’s subjective symptomatology, then the blood test becomes useful because the preclinical phase is defined almost entirely in terms of neuro-biomarkers.

However, that’s very often a difficult conversation because they might feel you’re withholding something, but there’s no disease-modifying agent apart from aducanumab, which is not particularly effective. The main thing is the symptomatic treatment, from a therapeutic point of view.

DL:

Yes, we won’t go into why the drug was so quickly ticked off as effective for Alzheimer’s disease. It’s one of those mysteries in life, isn’t it?

MS:

I think it was a kind of a quasi-emergency thing on the part of the US Food and Drug Administration. Just do something, something … anything! However, I think it is effective in a small number of patients. I’ve heard people say “I wouldn’t give that to one of my relatives!” but…

DL:

Do you subscribe to the type 3 diabetes model of insulin resistance and dementia?

[(Type 3 diabetes is a title that has been proposed for Alzheimer’s disease that results from resistance to insulin in the brain. It is not yet a medical term or a recognised condition, but is a term now used in research looking into the causes of Alzheimer’s disease]

MS:

That is a big issue. There were grants for dementia initiatives that were looking at risk prevention, and diabetes certainly surfaced as one of the major risk factors in dementia for early appearance and severe symptomatology. Metformin was certainly on the research agenda. I don’t know, to what extent that’s become clinically useful, but certainly, diabetes is a major, major issue.

DL:

Do you have any final messages for our listeners?

MS:

I think for those people not used to referring to neuro-psychology, this has become a very important discipline within the dementia world. In fact, it’s become very sophisticated over the years for many sorts of brain conditions with behavioural and cognitive symptomatology and referral is worthwhile. Some people might be reluctant; there was a time, many years ago, when I think it wasn’t that productive, but things have changed dramatically since then. Referral is always worthwhile and always welcome from our point of view.

DL:

Well, I am truly thankful for neuro-psychological assessments and their help in diagnosis, because I can tell you, Michael, it’s not a diagnosis I would love to make by myself. Therefore, as you’re quite rightly said, being absolutely clear that we are correct about a diagnosis is essential.

MS:

Yes, it is. The same sentiment applies to ourselves; it really is a big team effort in these days, as you know, with the neuro-imaging and neuro-biomarkers. It’s become a team diagnosis really.

We would like to thank Professor Michael Saling very much for his expertise and time.

This was first published on Healthed. To listen to the full episode, click here.