Cognitive Change in Huntington’s Disease

Cognitive change in Huntington’s: why it is not a memory problem

A woman with Huntington’s disease sits a brief cognitive screen at her GP’s surgery and scores within the normal range. She also has not opened her mail in four months, cannot start cooking without being told to, has missed three appointments, and has had the same argument with her brother eleven times.

Both of those things are true at once, and the gap between them is the whole subject of this guide.

Cognitive decline affects everybody with Huntington’s disease — it is not a subset or a complication. But it fails in a particular pattern, and the pattern is almost the opposite of the one most people, including many clinicians, are looking for. GeneReviews describes it as resembling frontotemporal dementia far more than Alzheimer’s disease.

The consequences are practical and they are large. Assessments miss it. NDIS applications under-fund because of it. Families argue about things that are not arguable. Support plans get built around physical care for somebody whose main need is a human being to start things. And people with HD get called unmotivated, uncooperative, difficult and lazy for the whole of a fifteen-year illness.

What fails, and what does not

Executive function fails first and hardest. This is the set of abilities that organises everything else:

Planning and sequencing. Breaking a goal into steps and doing them in order. A person with HD may be entirely able to do each step of making a meal and unable to assemble them into making a meal.

Initiation. Converting an intention into an action. This is covered under apathy in behaviour and mental health because it is frequently read as a mood problem, and it is a frontal one.

Set-shifting. Switching from one task, topic or approach to another. When this goes, the person gets stuck — on a topic, on a demand, on a grievance. This is perseveration, and it is the mechanism behind the same argument eleven times.

Working memory, holding and manipulating information over seconds.

Inhibition. Stopping an action already underway, or not starting one that should not be started. Behind the impulsivity, the falls, and a good deal of the social difficulty.

Mental flexibility. Generating an alternative when the first approach does not work.

Then, alongside it:

Slowed processing speed, which is pervasive and underestimated. A person with HD may be able to answer a question and need considerably longer to do it. Conversations run at other people’s pace, and the person drops out of them not because they cannot follow but because they cannot keep up.

Attention and distractibility, affected early.

Visuospatial difficulty, which affects navigation, judging distances, and recognising where things are.

And memory, which fails differently. This is the part most worth understanding. In Huntington’s, retrieval is affected rather than storage. The information went in; getting it out again on demand fails. Which means cues and extra time genuinely help — a prompt, a first letter, a multiple choice, a reminder of the context, and the memory surfaces. GeneReviews notes memory loss in HD is usually milder than in Alzheimer’s disease.

What is relatively preserved, and for a long time:

Language. Vocabulary, grammar and comprehension stay largely intact until late, when word-finding problems and simpler sentence structure appear. Speech becomes hard to produce because of dysarthria, which is a motor problem, not a language one. This distinction is constantly missed and it is why people with HD get spoken to as though they were cognitively absent.

Recognition of people. Unlike Alzheimer’s, people with HD generally know who everybody is.

Emotional understanding of their situation, often painfully intact.

And long-term personal memory.

Why standard screens mislead

Short cognitive screens are built around memory, orientation and language, because they were developed to detect Alzheimer’s disease. A person with Huntington’s will often do reasonably on them, for exactly the reasons above: they know the date, they know where they are, they know who the Prime Minister is, and with a cue they can recall the three words.

What the screen does not test: whether they can plan a week, start a task, stop an argument, switch from one thing to another, or hold a sequence together.

The practical consequences of this are serious.

A normal screen gets recorded, and it then functions as evidence that cognition is intact — which closes down the question for everybody who reads the file afterwards.

NDIS applications under-fund. This is the big one. A person whose main need is a human being to initiate, sequence and supervise gets assessed as needing equipment and some personal care, because the executive impairment was never measured. See Huntington’s disease and the NDIS.

Capacity assessments go wrong in both directions — somebody is found to have capacity because they can discuss a decision articulately, while being unable to carry out any part of acting on it; or found to lack capacity globally when the impairment is specific.

What to ask for instead. A neuropsychological assessment that tests executive function explicitly. Ask for it by name, ask that it address executive function and processing speed rather than general cognition, and ask that it include information from a family member about day-to-day function, because that is where the impairment shows. Clinicians working in HD also use the Unified Huntington’s Disease Rating Scale, whose total functional capacity component tracks real-world function over time and is worth having recorded as a baseline.

The insight problem

Lack of awareness of one’s own deficits is common in Huntington’s disease, and it is the single thing that most shapes how families experience the condition.

It is not denial. Denial is a psychological defence against knowledge. This is an impairment of the brain’s ability to monitor its own performance — the self-assessment system is part of what is damaged. Which means there is no hidden accurate self-knowledge to appeal to, and no amount of evidence can produce it.

What it looks like. Insisting on driving. Insisting they can still manage the finances, after the power has been cut off. Not accepting that they need help with showering. Not accepting that the movements are visible. Reporting at an assessment that everything is fine, and meaning it. Becoming angry at suggestions of help, because from the inside the suggestion is baseless and insulting.

Why arguing cannot work. There is no belief that evidence could change, because the mechanism that would register the evidence is impaired. Every family tries anyway, repeatedly, for years, and it generates enormous conflict and no change.

What works instead:

Change the environment rather than the mind. If driving is unsafe, the route is an occupational therapy driving assessment and the licensing authority, not persuasion. If the finances are failing, the route is an enduring power of attorney already in place, not a conversation about budgeting.

Externalise the authority. “The doctor says you can’t drive until the assessment” lands better than “I don’t think you should drive,” and more importantly it takes the conflict out of the relationship and puts it onto an institution. This is not dishonesty; it is accurate attribution.

Offer help as service rather than as rescue. “I’ll do the forms, you check them” is accepted far more often than “you can’t do the forms.”

Let small things go. Not every inaccuracy needs correcting. Most do not.

And do the legal documents early. This is the practical reason insight matters more in HD than in most conditions: enduring power of attorney and enduring guardianship require capacity, and the window closes while the person still looks and sounds entirely capable. Covered below.

Capacity, and the closing window

Here is the thing to act on.

Huntington’s produces a long illness — a median of 15 to 18 years. That length creates a false sense of time. But the executive and insight changes come early, often before the movement disorder is obvious, which means the capacity to make and understand complex decisions can be compromised years before the person looks unwell.

So the documents go first, not somewhere in the middle:

An enduring power of attorney for financial and property decisions.

An enduring guardianship, or your state’s equivalent, for health, medical and personal decisions.

A will, reviewed or made.

An advance care directive, recording treatment preferences — hospital admission, antibiotics for chest infections, feeding tubes, resuscitation, where the person wants to be cared for.

Do these in the first months after diagnosis, with a solicitor rather than a template, and while capacity is beyond question — because a document signed once cognitive change is apparent is a document that can be challenged, which is precisely the outcome it existed to prevent.

And understand that capacity is decision-specific. A person with HD may have capacity to decide where to live and not to manage a share portfolio, or capacity to consent to treatment and not to sign a contract. A global finding of incapacity is usually wrong and usually unnecessary. Where there is doubt, a formal capacity assessment addressing the specific decision is the right instrument, and a solicitor or the state civil and administrative tribunal can advise on process.

What helps, day to day

Almost everything useful here is about putting the structure outside the person’s head.

Routine, unvarying. The same order, the same times, the same places. Routine is not a comfort in HD; it is a substitute for the executive function that would otherwise organise the day.

Warning before any change. Reduced set-shifting makes unexpected change genuinely difficult. A day’s notice, then a morning’s notice, then a reminder.

One thing at a time. One instruction, one question, one task. Multi-part requests fail — not because the person cannot do the parts but because holding the sequence has gone.

Break tasks down and prompt each step. “Let’s get dressed” may produce nothing. “Here’s your shirt” produces a shirt going on.

Prompt rather than do. If they can do the step once started, let them. Doing it for them removes it permanently.

Wait. Processing is slow. The most common failure in conversations with people who have HD is the other person filling the gap, answering their own question, or moving on. Count to ten.

Cue memory rather than testing it. Do not ask “do you remember what we said about Thursday?” Say “on Thursday we’re going to the clinic, remember we talked about it.” Retrieval is the problem; providing the cue solves it.

Write things down and put them where they will be seen. A whiteboard with today’s date and today’s plan. A single calendar. Lists.

Reduce choices. Two options, not eight. An open question like “what would you like to do today?” can be genuinely impossible; “shall we go to the shops or stay home?” is answerable.

Keep the environment consistent. Same place for keys, wallet, glasses, phone. Visual clutter removed.

Reduce distraction. Television off during conversation. One person talking at a time.

And do not argue the unarguable. With insight gone, producing evidence achieves nothing. Change the situation instead.

What else might be contributing

Before concluding that a change is progression, several reversible things should be checked — and in Huntington’s they are checked less often than they should be.

Depression, affecting around 40 per cent of people with HD, which produces poor concentration, slowed thinking and apparent memory failure. Treatable, and treating it is frequently the highest-value intervention available in HD.

Medication. Antipsychotics, tetrabenazine, benzodiazepines, anticholinergics and sedating antidepressants all slow cognition. Reviewing the list costs nothing and occasionally settles the whole question. See movement and chorea in Huntington’s.

Sleep disturbance, which is common in HD and significantly degrades thinking.

Infection, especially urinary, which can cause delirium that looks like a sudden cognitive decline.

Dehydration and constipation.

Weight loss and inadequate nutrition, which are substantial in HD and affect cognition. See eating, weight and swallowing.

Pain, which consumes attention.

And alcohol, which is discouraged in HD and which some people are using more of as mood and impulse control deteriorate.

A sudden change over days is almost never Huntington’s progressing. Progression in HD is slow. Sudden change means look for a cause.

Money, and why it goes wrong early

The clearest practical consequence of executive impairment in Huntington’s, and the one that does the most damage before anybody connects it to the illness.

What goes wrong, and in roughly this order. Bills stop being paid, not because the money is not there but because paying them requires initiating, sequencing and remembering a deadline. Statements stop being opened. Then impulsive spending appears, from loss of inhibition — large purchases, subscriptions, gambling in some people, money given away. Then judgment about value goes, which makes somebody vulnerable to scams and to anybody who asks. Then the capacity to understand a financial decision goes, while the capacity to sign something remains.

Why it is usually missed. Because the person can still discuss money articulately. They can explain what a mortgage is and what their income is, and at an assessment they present as entirely competent. What they cannot do is the sequence of actions that constitutes managing money, and nothing in a conversation reveals that.

The damage is frequently severe by the time it is noticed — defaults, a lost house, superannuation withdrawn and spent, debts in a partner’s name, a business failing. And it is usually not recoverable.

What to do, and the order matters:

Enduring power of attorney, now. This is the instrument. It must be signed while the person has capacity, which is why it goes in the first months after diagnosis rather than when the problem appears — a document signed once cognitive change is apparent can be challenged, which defeats the point.

Simplify everything. One account for bills with automatic payments set up. A separate account with a limited balance for spending. Direct debits for everything that can be automated.

Reduce the available instruments. Lower credit card limits, remove overdrafts, cancel unused cards, turn off one-click purchasing and in-app payments.

Set up notifications to a second person for transactions over a threshold — most Australian banks offer this.

Talk to the bank. Banks have processes for customers with cognitive impairment and will often set up protections if asked. Most families never ask.

Check for gambling specifically, and use self-exclusion schemes if it is present. Impulse control loss plus online betting is a recognised and destructive combination.

And get a financial counsellor, which is free, if debt has already accumulated. The National Debt Helpline is on 1800 007 007.