What is Huntington’s disease?

Huntington’s disease is a serious, inherited condition which stops parts of your brain from working properly over time due to progressive damage. The disease is degenerative, meaning your symptoms gradually get worse. You are likely to need a lot of professional support towards the later, more advanced stages of the condition. According to the NHS, Huntington’s disease is usually fatal after a time period of up to 20 years from its onset. 

The symptoms of Huntington’s disease start to appear during adulthood, usually between the ages of 30-50 years, although in rare cases it is possible for symptoms to begin much earlier or later. Common symptoms of Huntington’s disease include: impaired concentration and memory, depression, impaired motor coordination, involuntary jerking motions, mood swings, problems with swallowing, speaking and breathing, and difficulty moving. 

There are currently no known cures for Huntington’s disease and there is no way to stop the symptoms from getting worse over time. If you, or a loved one, are affected by Huntington’s disease this can be a very difficult time; for additional information and support regarding dealing with a diagnosis of Huntington’s disease, you can visit The Huntington’s Disease Association.

Importance of sleep in Huntington’s disease

According to the Mental Health Foundation, sleep is just as important for us as eating, drinking, and breathing. Sleep is important for the brain for several reasons including: enabling adequate removal of waste products from the brain through the glymphatic system, memory consolidation, brain development, and emotional regulation.¹

Most adults need between 7-9 hours of sleep every night; getting the recommended amount of sleep is very important for both your physical and mental health.² A lot of the time, any health benefits that are associated with foods or lifestyle choices require consistency over longer periods of time for us to notice, however, regarding the benefits of adequate sleep: most of us report feeling better immediately after getting a good night’s sleep. This highlights the importance of sleep, even if you are completely healthy. However, for those with neurodegenerative conditions like Huntington’s disease, it might be even more important for you.

There is an increasing body of evidence suggesting that neurodegenerative diseases, like Huntington’s disease, can cause sleep abnormalities. Inadequate sleep can then exacerbate neurodegeneration, making you feel even worse even quicker.³ Due to this vicious cycle of Huntington’s disease causing sleep abnormalities and sleep abnormalities making the condition worse, there is a growing interest in the use of sleep therapies to help people affected by Huntington’s disease.

Types of sleep disturbances in people with Huntington’s disease

Sleep disturbances are reported in some people from the earlier stages of Huntington’s disease, with some people experiencing problems with their sleep even before the onset of other clinical symptoms.⁴

The most common sleep issues experienced by people with Huntington’s disease include:

• Insomnia: regular difficulty with falling asleep and/or staying asleep
• Frequent nocturnal awakenings: this is a very common feature of insomnia and may occur due to increased motor activity during sleep. Increased motor activity during sleep is more common among people with Huntington’s disease because restless leg syndrome is sometimes a feature of Huntington’s. Restless leg syndrome describes an overwhelming urge to move the legs, due to feeling strange sensations and can be particularly disruptive at night
• Excessive daytime sleepiness: people with Huntington’s may fall asleep repeatedly during the day

Why are sleep disturbances associated with Huntington’s disease?

Huntington’s disease is marked by harmful changes to the brain. Certain parts of your brain need to be working properly, in order for you to fall asleep and to stay asleep. It is currently thought that the changes in certain parts of the brain over the course of the disease, mean that people with Huntington’s disease struggle with their sleep.

The following parts of the brain are known to be important in sleep:⁵

• Hypothalamus: the hypothalamus contains clusters of thousands of cells which are collectively called the suprachiasmatic nucleus (SCN). The SCN obtains information about light exposure (from the eyes) to control your sleep pattern. Some people with damage to the SCN sleep erratically throughout the day because they are unable to match their circadian rhythms (your natural biological clock) with the external light-dark cycle
• Brainstem: this is found at the base of the brain and communicates with the hypothalamus to orchestrate the transition between waking and sleeping. The brainstem is also important in REM sleep - it sends signals to relax the muscles which are essential for body posture and limb movements, so that we don’t physically act out our dreams as they are happening
• Thalamus: the thalamus serves as a relay station in the brain, allowing information from the body to be passed and processed through the brain. During most stages of sleep, the thalamus becomes quiet, letting you tune out the external world
• Pineal gland: when this part of the brain receives signals from the SCN, it increases the production of a hormone called melatonin. An increased production of melatonin helps you fall asleep

Huntington’s disease is known to affect the hypothalamus, with some studies showing evidence of hypothalamic atrophy in people with Huntington’s disease.⁶ Atrophy of the hypothalamus can affect the functioning of other brain regions too, including the pineal gland. This is because the suprachiasmatic nucleus of the hypothalamus influences the activity of the pineal gland. Furthermore, there is evidence to suggest that Huntington’s disease also causes atrophy of the brainstem and thalamus, the severity depends on how advanced the disease is.⁷

Atrophy of all these brain structures can cause the sleep disturbances that are associated with Huntington’s disease, due to the respective roles of these structures in ensuring adequate sleep.

Managing sleep disturbances in Huntington’s disease

There are several options available to you if you have been diagnosed with Huntington’s disease and are consequently struggling to achieve adequate sleep. These options include:

• Dopamine agonists: dopamine agonists may be prescribed to treat restless leg syndrome; dopamine agonists are medications which increase your levels of dopamine, which is usually low in people with restless leg syndrome. By treating restless leg syndrome, you may sleep better as you’ll be less likely to be disturbed by the motion of your legs. Examples of dopamine agonists include ropinirole and pramipexole
• Melatonin: melatonin can be taken in tablet form. Melatonin is a hormone which is naturally produced when it’s dark and higher levels of melatonin in your body help you to sleep. By taking melatonin tablets, this will add to your body’s natural production of melatonin and help you fall asleep, and improve your quality of sleep
• Sleep hygiene: having a regular sleep routine is beneficial for improving your sleep. Examples of good sleep practices include going to bed and getting out of bed at fixed times everyday, avoiding using electronic devices immediately before bed, sleeping in an environment that is cold, quiet and dark (although this may depend on individual preference, these are the conditions that are generally recommended to the public). Additionally, having a good diet and exercising as much as possible can help you to relax and wind down at bedtime (although exercise and any motor activities are likely to be very challenging towards the end stages of Huntington’s). Furthermore, you should avoid large meals or strenuous exercise soon before going to bed
• Light therapy: there is some evidence to suggest that light therapy can be effective in regulating your circadian rhythms which control your sleep-wake cycle. It is currently believed that light therapy encourages your brain to produce less of the sleep hormone melatonin, and to produce more serotonin – a hormone that regulates your mood. As a result, light therapy may help people improve their sleep, and improve their mood. For more information on light therapy, see here

Summary

• Huntington’s disease is a serious, inherited condition which stops parts of your brain from working properly over time due to progressive damage. There is no cure for Huntington’s disease
• Huntington’s disease is associated with sleep disturbances: people with Huntington’s may have difficulties falling asleep, and staying asleep. Also, people with Huntington’s disease may experience excessive daytime sleepiness
• Huntington’s disease is thought to be associated with sleep disturbances due to changes in the brain, for example abnormalities of the hypothalamus and brainstem
• Sleep disturbances can be managed using dopamine agonists, melatonin, practicing good sleep hygiene, and light therapy