Movement and Chorea in Huntington’s Disease

Movement and chorea in Huntington’s: falls, equipment and the treatment trade-off

Chorea is the thing everybody associates with Huntington’s disease, and it is frequently not the thing causing the most trouble.

Chorea itself — the involuntary, flowing, irregular movements that are the hallmark of HD — is often less disabling than the problems with voluntary movement that accompany it. A person can usually live with their hands moving. What limits them is being unable to control the movement they intend: the loss of fine motor accuracy, the slowed and imprecise reaching, the gait that will not hold a straight line, the speech that will not form properly.

And the central clinical fact about treating chorea is one that surprises people: reducing it is not automatically a good idea. The drugs that suppress chorea work by depleting dopamine, and depleting dopamine can worsen depression, apathy and parkinsonism. In a condition where depression affects around 40 per cent of people and apathy is among the strongest predictors of support need, trading movement for mood is a real decision rather than an obvious win.

This guide covers what the movement disorder actually consists of and how it changes over fifteen years, why people with HD fall and what prevents it, the treatment trade-off in detail, the equipment that survives chorea, and what physiotherapy and occupational therapy actually contribute.

What the movement disorder consists of

Chorea. Involuntary, irregular, non-rhythmic movements that flow from one body part to another. Present in most people with HD, usually worsening over the first ten years, occurring during waking hours only, impossible to suppress voluntarily, and worse under stress. Early chorea is subtle — a finger movement, a shoulder shrug, a facial grimace, a shift of the trunk — and is frequently mistaken for fidgeting or a nervous habit. People sometimes incorporate it into apparently purposeful movement, which is called parakinesia and which makes it even harder to spot.

Impaired voluntary movement. Affected early and often more disabling than the chorea: slowed initiation, reduced accuracy, loss of fine motor control, difficulty with rapid alternating movements. This is what makes buttons, cutlery, keyboards, writing and phones hard.

Dysarthria. Slurred, effortful, imprecise speech, present early. Covered alongside swallowing in eating, weight and swallowing.

Gait and balance problems. A wide-based, irregular, lurching gait, poor postural stability, and difficulty correcting a loss of balance. This is where the falls come from, and it is covered in detail below.

Oculomotor abnormalities. Difficulty initiating saccades, slow eye movements, undershooting a target, difficulty maintaining fixation. Present in up to 75 per cent of symptomatic people and among the earliest objective signs. They also have a practical consequence nobody mentions: somebody who cannot move their eyes efficiently cannot scan an environment, read fluently, or track what is going on around them, which contributes to apparent inattention.

Hyperreflexia, early, in around 90 per cent.

Then the shift. As HD advances, chorea often declines and is replaced by dystonia — sustained abnormal postures, frequently of the neck, trunk and limbs — along with bradykinesia and rigidity. This matters because families and services sometimes read decreasing chorea as improvement. It is not; it is progression, and the rigid-dystonic phase is generally more physically disabling than the choreic one. The akinetic-rigid form of HD present from the start, more common in juvenile onset, is sometimes called the Westphal variant.

And in the late stage, people are typically totally dependent for mobility and transfers, often unable to speak, and incontinent.

Why people with Huntington’s fall

Falls in HD are frequent, serious and systematically under-analysed, because they get attributed to chorea when chorea is usually the least of it.

What actually causes them:

Impaired postural reflexes. The automatic correction that stops you falling when you trip is damaged. This is the big one, and it means somebody with HD who starts to go over does not catch themselves.

Gait instability, wide-based and irregular.

Executive dysfunction and impulsivity. This is the most underestimated factor by a distance. A person with intact insight assesses a situation before standing up and walking across a cluttered room. A person with HD may stand up and go, immediately, without having assessed anything — not because of poor balance but because the pause between intention and action has gone. Which is why falls in HD are a cognitive problem as much as a motor one, and why equipment alone does not solve them.

Reduced awareness of deficits. Somebody who does not perceive themselves as unsteady will not use the frame.

Impaired visual scanning, from the oculomotor problems, so obstacles are not seen.

Dual-tasking failure. Walking while carrying something, or walking while talking, is substantially harder than walking.

Medication. Antipsychotics and tetrabenazine cause sedation, orthostatic hypotension and parkinsonism, all of which increase falls. A fall is a reason to review medication.

Weight loss and muscle wasting, which are substantial in HD.

What actually helps, in rough order of effect:

Removing hazards rather than teaching caution, because caution requires the insight and the pause that may not be available. Clear floors, no loose rugs, no trailing cords, furniture arranged to give continuous support along routes, nothing stored low or high.

A clear path to the toilet, lit at night. Nocturnal toilet trips are where a disproportionate share of falls happen.

Grab rails everywhere they would be used, fitted by an OT rather than guessed at.

Hip protectors, which are unglamorous and reduce fracture risk.

Seating the person uses by choice. A chair that is comfortable, supportive and easy to get out of reduces the number of risky transitions.

Physiotherapy focused on gait, transfers and strength, which has evidence behind it in HD and is usually under-provided.

Reviewing medication after any fall.

And accepting a level of risk deliberately rather than by default. This is the honest part. A person with HD who is mobile will fall sometimes. Eliminating that risk means immobilising them, which costs more than it saves. The 2020 gap analysis for Huntington’s Victoria recorded that the NDIS and aged care systems were both described as a poor fit for HD particularly around risk and choice, and that is exactly the tension. The right approach is a documented, discussed decision about acceptable risk, made with the person while they can participate, rather than a restriction imposed after an incident.

The treatment trade-off

What is available for chorea. Tetrabenazine, deutetrabenazine and valbenazine, which are VMAT2 inhibitors and work by depleting dopamine. Typical and atypical antipsychotics, which block dopamine receptors and also treat irritability and psychotic symptoms, which is sometimes a useful double effect. Benzodiazepines, for short-term or situational use. In Australia, tetrabenazine is PBS-subsidised.

What the trade-off is. Dopamine depletion can cause or worsen:

Depression, which is the one that matters most. Tetrabenazine in particular carries a recognised association with depression and suicidal ideation. In a condition where depression already affects around 40 per cent of people and where suicide risk is elevated — GeneReviews notes risk peaks around diagnosis and when independence is lost — this is a serious consideration, not a footnote. Anybody started on tetrabenazine should have mood actively monitored, and families should know to report change promptly.

Apathy, which is already common in HD and worsens with disease stage, and which drives support need more than chorea does.

Parkinsonism — slowness, rigidity, reduced facial expression — which can impair function more than the chorea it replaced.

Sedation, which worsens cognition and increases falls.

Swallowing difficulty, in a condition where aspiration pneumonia is a frequent cause of death.

So the question to ask before starting treatment is not “is there chorea?” but “is the chorea causing harm?” Harm means: interfering with eating or drinking, interfering with sleep, causing injury, causing falls, causing weight loss through energy expenditure, causing pain, or causing distress to the person themselves. Chorea that is visible but not doing any of that may be better left alone.

And the corollary: if chorea is causing harm, treat it, and treat it properly, with mood monitored. Under-treatment of genuinely harmful chorea is also a failure.

Things to avoid. Levodopa-containing drugs, which can worsen chorea. MAO inhibitors. Alcohol is discouraged.

What else is on the medication list for the movement disorder: sodium valproate or levetiracetam for myoclonus, and botulinum toxin for focal dystonia in some cases.

The conversation worth having is with a neurologist or HD service, with the person and the family present, framed as: what is the chorea actually costing, what would the drug cost, and shall we try it and review in six weeks with an agreed measure of whether it helped. That is a different conversation from “there are drugs for chorea, would you like some.”

Equipment that survives chorea

Equipment prescription in Huntington’s is genuinely different from other neurological conditions, because the equipment has to cope with unpredictable involuntary movement, with impulsivity, and with reduced insight. Standard prescriptions frequently fail.

Wheelchairs. The usual problem is that a person with chorea in a standard wheelchair is at risk of injuring themselves against the frame, sliding out, or tipping the chair. What helps: a wider and deeper seat, padded armrests and side panels, a solid supportive back rather than a sling, a tilt-in-space frame which is far more stable and lets position be changed without transferring, anti-tip devices, and secure but non-restrictive positioning. Where a belt or harness is being considered, be clear that this may be mechanical restraint and triggers the restrictive practice framework, including authorisation and reporting — see behaviour support and restrictive practices. Positioning for safety and comfort is not the same thing as restraint, and the distinction has to be documented by a prescribing OT rather than assumed.

Beds. Low beds, or a mattress on a platform, reduce injury if somebody comes out of bed. Padded bed rails rather than bare metal, where rails are appropriate — again with the restraint question considered. An adjustable profiling bed later.

Padding, generally. Walls, bed ends, chair arms, doorframes on habitual routes. People with significant chorea sustain bruising and sometimes fractures from contact with ordinary furniture, and this is cheap to prevent.

Seating in the living area. A deep, well-padded, supportive chair with sides. Recliners with high backs. Avoid lightweight chairs that slide or tip, and avoid hard arms.

Eating equipment. Weighted cutlery, which dampens involuntary movement. Non-slip mats. Plate guards. Cups with lids and wide bases. Two-handled cups. Straws. All of this is covered further in eating, weight and swallowing.

Bathroom. A shower commode chair with good trunk support, used earlier than in other conditions because standing showers become unsafe early. Non-slip surfaces. Grab rails positioned by an OT. A level-entry shower where modification is possible.

Communication equipment, where dysarthria is significant. Access method matters enormously in HD: a touchscreen is hard to use accurately with chorea, so switch access with a well-positioned switch, or a keyguard, or partner-assisted approaches may work better. An OT and speech pathologist should specify this together.

Environmental controls operated by voice or switch, which restore some independence when fine motor control has gone.

And the general principle: in HD, specify for durability, padding and stability rather than for lightness and elegance. Equipment that would suit somebody with multiple sclerosis or a spinal cord injury frequently fails here. Ask for an occupational therapist with movement disorder or HD experience, and if there is not one locally, ask the specialist HD service or Huntington’s Australia on 1800 244 735 who prescribes well for this condition.

Physiotherapy and occupational therapy

Both are under-provided in HD and both have more to offer than most people are told.

Physiotherapy. Gait and balance training, strengthening, transfer practice, falls prevention, and in later stages positioning, contracture prevention and respiratory physiotherapy. There is a reasonable evidence base for exercise in HD, and it is one of the few things that is unambiguously good for the person. Maintenance physiotherapy over years, rather than a block of six sessions after a fall, is what actually helps — and that means asking for it as an ongoing item in an NDIS plan rather than as an episode of care.

Occupational therapy. Equipment prescription as above, home assessment and modification, routines and task simplification, environmental controls, and — the part most specific to HD — structuring the environment to compensate for executive dysfunction. Visual schedules, consistent placement of objects, reducing choices, simplifying sequences. See cognitive change in Huntington’s.

Both, together, early. The common pattern is that allied health arrives after a crisis. In a fifteen-to-eighteen-year condition there is time to do this properly, and the arrangements that work best are the ones set up while the person can still participate in deciding them.

Sleep, and why it is worth treating properly

Sleep disturbance in Huntington’s is common, under-treated, and the thing most likely to be making everything else worse.

What goes wrong. People with HD frequently take a long time to fall asleep, wake repeatedly through the night, sleep less in total, and have a fragmented and shifted sleep-wake cycle — up at 3am, asleep in the afternoon. Chorea reduces during sleep but the movement around sleep onset can delay it. Depression, anxiety and the medications used for both all affect sleep. And late in the disease, the sleep-wake rhythm itself can break down.

Why it compounds everything. Poor sleep worsens processing speed, concentration, memory retrieval, irritability and mood — which is to say it worsens every other domain of the condition. A substantial share of what gets recorded as cognitive decline or behavioural deterioration in HD is sleep deprivation, and sleep deprivation is treatable.

It also breaks households. A person who is awake and active at 3am means a carer who is awake at 3am. Sleep is the most common reason home arrangements stop being viable, and it is the thing most worth intervening on early.

What to do:

Treat it as a clinical problem rather than a lifestyle one. Raise it specifically with the neurologist or HD service. Mirtazapine is used for insomnia in HD, and short-term zopiclone or melatonin for sleep disturbance.

Review the medication list. Several drugs used in HD are sedating during the day and disrupt night-time sleep, and the timing of doses matters.

Check for pain, needing the toilet, and restless legs, all of which are common and all of which are fixable.

Get the environment right. Consistent bedtime, consistent waking time, light exposure in the morning, dark and quiet at night, no screens late, and the room set up so a night-time trip to the toilet is safe and lit.

Deal with the nights properly in the support plan. Overnight support funded honestly, on the basis of a fortnight of night logs rather than an estimate. See supported independent living with Huntington’s.