Understanding Sleep Movement Disorders - Doctor Q&A

Night-time movements: Understanding sleep-related events

Sleep-related movement disorders are conditions where repetitive movements affect a person’s sleep.

One example is Restless Legs Syndrome (RLS), a sensory-motor neurological disorder that causes an overwhelming urge to move the legs. It often begins at a very young age but is mostly diagnosed in the middle or later years.

• Early-onset RLS occurs below the age of 45
• Late-onset RLS occurs above 45

When an involuntary twitching or jerking of the legs occurs during sleep, it is known as Periodic Limb Movements in Sleep (PLMS). Up to 80 per cent of RLS patients have PLMS.

Both RLS and PLMS can disturb sleep by causing sleep-initiation insomnia and sleep maintenance insomnia respectively.

Other sleep movement disorders include bruxism (clenching or grinding of teeth during sleep), neck myoclonus (sudden jerks of the neck when drowsy or trying to fall asleep), leg cramps and hypnic jerks (muscle spasms during sleep).

If you have questions about sleep-related events such as:

• Acting of dreams
• Various movements occurring in sleep
• Sleep waking or talking
• Restless legs and sleep-related leg jerks
• Excessive day time sleepiness

Don't miss this chance to ask Dr Tushar Gosavi in this Q&A forum!

Dr Gosavi Tushar Divakar is Senior Consultant, Department of Neurology, at the National Neuroscience Institute (NNI@SGH) and Deputy Head, Ambulatory Services (Neuroscience Clinic@SGH).

Dr Tushar is a neurologist with special interest in epilepsy and sleep medicine and has acquired masters in sleep medicine from Oxford University.

1. Question by Charles

Hi Dr,

I would like to ask what is the best treatment, if any, for the grinding of teeth during sleep?

I've had this problem since young and sometimes I wake up in the middle of the night with ear pain.

I'm on Anarex every night now, but wonder if there is a better solution. Thank you!

Answer by Clin Asst Prof Tushar

Hello Charles,

Grinding of teeth or “Sleep bruxism” is seen in about 8% of adults. Most important aspect would be to ascertain that it is not secondary to another sleep disorder like obstructive sleep apnea (OSA); hence if you have additional symptoms like snoring, non-refreshing sleep or daytime sleepiness, medical attention should be sought.

There is no easy treatment to stop bruxism from occurring. Simple measures like a good sleep hygiene, avoidance of certain triggers (eg alcohol, smoking, caffeine) should be considered when present. Few medications might help but usually not recommended for long-term use, considering the side effects and benefits. Lastly seeing a sleep dentist might be a good idea to assess the impact of bruxism on tooth (eg tooth wear). Sleep dentists might also suggest some appliances to protect the teeth.

Your history of taking Anarex every night (long term use) is something that needs to be reviewed- as taking paracetamol containing tablet (or any painkiller tablet) daily for extended periods might put you at risk of analgesic overuse headache- a type of headache that may potentially occur in anyone who consumes more than 15 painkiller tablets per month for more than 3 months at a stretch.

2. Question by Jacqueline

Hi Dr,

I sleep alone in my bedroom. I have retired since 2021 and during one overseas holiday with one of my daughters (we share a twin room), she told me I sleep talk practically every night. And sometimes I screamed.

When I travelled with my sister and slept in a twin room, she also told me that I act out the dreams as I swing my arms and kicked my legs, gesturing and talking in my sleep. And sometimes I screamed. 

Once, with another daughter in a red-eye flight, I wanted to get out of my seat and was shouting something, which my daughter quickly pulled me back into the seat. Of course, it brought the air stewardess and air steward to check if I was alright.

But all these while, most times I did not know what happened. On a few occasions, as I woke up in the midst of these happenings, I vaguely recalled what happened in the last few moments of the dreams.

When I am back home sleeping alone, I tried to use the security camera to record such happenings. But I somehow didn't manage to record it. And when I forgot to setup the camera, it seem that there was such happening as I woke up in the midst of it. But most times, I just fell back to sleep.

Are these related to Sleep Movement Disorder? Will such happening be dangerous as I vaguely remember occasions where I walked to the door to try to open it.

Appreciate your advice and whether I should seek consultation with a doctor and where can I go for the consultation.

Answer by Clin Asst Prof Tushar

Hello Jacqueline,

I don’t know your age, but most of your symptoms are suggestive of a condition called REM behaviour disorder (REM-BD). In this condition, people act out their dreams. Only one unusual thing from your history is the fact that sometimes you walked to the door and tried to open it - this seems like a purposeful type of movement more suggestive of another sleep disorder called non REM parasomnia (sleep walking).

If doubt exists purely based on history/ account of eyewitnesses, an overnight sleep study might be useful to confirm the diagnosis.

In REM-BD, one does not have the normal muscle atonia (loss of muscle tone) which is expected to be present during the dream stage (REM stage) of sleep. As a result, one does the actions that correlate to their dream content. One may not be aware of the episode if not woken up, but if woken up during the event, you might recollect the dream. As later half of our sleep contains more REM sleep, these events tend to occur in the later half of sleep, more towards the early morning hours. The frequency varies from once in a while to few episodes every night.

REM- BD by itself may not always need medical treatment, especially if mild and infrequent. Risk of injuries to the patient and bed partner is an important concern if the behaviours consist of vigorous movements or falls.

If frequent and/or intense actions occur, there are a few medications available to reduce the episodes.

With regards to the cause, REM-BD can be an isolated disorder, but certain medications (particularly antidepressants), other sleep disorders like narcolepsy might be the cause. Extremely rarely it may occur after brain lesions in certain specific brain areas concerned with sleep mechanisms.

I would recommend that you see a sleep neurologist for your symptoms, if the symptoms are frequent and troublesome, so that the doctors can discuss with you about further workup and treatment options if needed.

Safety is important and you should keep your bedroom free of potential hazards to minimize risk of injuries.  Remove all dangerous/ sharp, heavy or hard objects from the vicinity of your bed, apply soft padding to all the sharp or hard edges around your bed, ensure your windows are secure, use a low bed, and put a mattress or soft carpet on the floor. Bed partners are also at risk of injuries and precautions should be taken in this aspect as well.

A good sleep hygiene in general is helpful.

3. Question by LW Ong

Hi Dr Gosavi Tushar Divakar

I am a 63-year-old male. I have experienced acting of dreams occasionally which could be punching with my fist or kicking with my leg. But I actually injured myself during an overseas trip for the first time recently when I swung from the bed and ended up on the floor during my dream of playing football.

Appreciate your advice on what are the potential medical problems I have and if I require any treatment to prevent hurting myself in the future. Thank you.

Answer by Clin Asst Prof Tushar

Hello Mr Ong,

Your symptoms are suggestive of a condition called REM behaviour disorder (REM-BD). In this, people act their dreams. This occurs due to the loss of the normal REM (dream) sleep related muscle atonia (loss of muscle tone), thus leading to actions that correlate with the dream content.

With regards to what causes REM-BD, it can be an isolated disorder, but certain medications (particularly antidepressants), other sleep disorders like narcolepsy, might be the cause. Extremely rarely, it may occur after brain lesions in certain specific brain areas concerned with sleep mechanisms.

The risk is causing injuries to yourself and your partner.

Safety is important and you should keep your bedroom free of potential hazards to minimize risk of injuries.  Remove all dangerous/ sharp, heavy or hard objects from the vicinity of your bed, apply soft padding on all the sharp or hard edges around your bed, ensure your windows are secure, use a low bed, and put a mattress or soft carpet on the floor. Bed partners are also at risk of injuries from the actions and appropriate measures should be taken to prevent this.

You may consider seeing a sleep neurologist, particularly if the symptoms are frequent and intense, or if they affect your sleep significantly leading to day-time tiredness, as there are medications available that help to reduce these episodes.

4. Question by Ang BL

Hi Dr,

I would like to know if I have a sleep disorder, please:  I am 72, male, a retired civil servant. I've retired more than 20 years ago, living very happily but I often have dreams at night related to my past one-and-only career, ie about the job nature, colleagues in the SAF etc. 

I also have dreams about my loved ones who have passed on regularly. I have 3 or 4 dreams at night almost on a daily basis, and I can recall pretty vividly about most of what I dreamt a night before. This has been going on for years and years.

I am otherwise healthy and have active outdoor activities nearly 5 days a week.  My questions are:  Is my situation common? Do I have a serious sleep problem? Do I need to see a doctor or specialist on the matter?  Thank you.

Answer by Clin Asst Prof Tushar

Hello Ang BL,

Are the dreams distressing? Do they wake you up from sleep causing disturbed sleep and daytime sleepiness? Also are there any instances where you were noticed to act dreams by your bed partner? If the answer is “no” to the above questions, then your symptom might more likely be a normal sleep related phenomena rather than a manifestation of any sleep disorder.

One normally goes through about 4 to 5 cycles of REM sleep during one night's sleep, and we dream during this stage of sleep. If your sleep is interrupted and you wake up often after a dream, you may remember your dream content which is may be a normal thing to happen.

Also, an important consideration would be to ensure you have a regular sleep-wake schedule, a good sleep hygiene and avoiding alcohol if needed. If you are on any medications, it is good to ask doctors if vivid dreams could be a side effect of the medications.

To summarise, having vivid dreams in isolation does not necessarily indicate a sleep disorder. However if you feel that the quality of your sleep is poor leading to a non-refreshing sleep and day time sleepiness, it would be better to see a sleep specialist.

5. Question by Sim

Hi Dr,

I get leg cramps - does drinking coconut water helps as is this due to potassium deficiency?

Sometimes I'm not sure if I'm awake or dreaming. Does conscious dreams mean I managed to catch some sleep? Thank you.

Answer by Clin Asst Prof Tushar

Hello Sim,

Painful muscle cramps in the legs during sleep are not uncommon. These can be troublesome and affect your sleep quality if they are frequent. The causes can be electrolyte imbalances involving calcium/potassium or magnesium, dehydration, thyroid disorders and diabetes, lumbar spine disorders; but quite frequently no clear cause is identified.

Coconut water has high potassium content. If your potassium levels tend to be on lower side coconut water might help. Certain medications such as diuretics used to treat hypertension or heart diseases might cause potassium to be low. But as mentioned above, there are more causes for leg cramps in sleep than potassium deficiency alone. So I am wondering if your potassium tends to be low in which case coconut water might be helpful.

Lifestyle measures are helpful in reducing nocturnal cramps. These include leg muscle stretching exercises before going to bed and regular physical exercise. Avoidance of alcohol, caffeine and exercising in extreme heat or exercising on hard concrete floors might also be useful. If these simple measures fail to work, and if your cramps are frequent and affecting your sleep, medical attention should be sought for consideration of further evaluation and for treatment with medications.

With regards to your second question, one dreams only in sleep. So if you are dreaming, it means you are asleep. Some sleep disorders lead to vivid dreams during the transition from wakefulness to sleep or viceversa, but these are associated with other symptoms like excessive day time sleepiness.

During one night, our sleep cycles through various stages, and one such stage called REM stage is the period during which we dream. As such, REM stage sleep is considered light sleep and its easy to wake someone up during this stage of sleep. This might be the reason for you feeling that you are having “conscious dreams”. This is not necessarily abnormal in isolation. But if you have additional symptoms like “acting of dreams” or excessive sleepiness in the day time,  then it would be advisable to consult a sleep specialist.

6. Question by SY Ong

Hi Dr,

I have had bruxism since young. Some nights have no teeth grinding but some nights do. The nights where I go to sleep exhausted and overtired, I fall asleep fast but will most likely experience unconscious teeth grinding for that night.           

a) What to do when I’m overtired to prevent poor sleep quality/bruxism?

b) Can any medicine help with bruxism (currently or in the future)?

Thank you for your advice.

Answer by Clin Asst Prof Tushar

Hello SY Ong,

Grinding of teeth or “Sleep bruxism” is seen in about 8% of adults. Most important aspect would be to ascertain that it is not secondary to another sleep disorder like obstructive sleep apnea (OSA); hence if you have additional symptoms like snoring, non-refreshing sleep or day time sleepiness, medical attention should be sought.

Medical treatment to prevent bruxism has limitations and is not highly effective as most medications ideally should no be given for long term usage. On the nights that you are overtired, some medications taken judiciously might help, but these do have side effects and you will have to see a sleep specialist for this. Simple measures like a good sleep hygiene, avoidance of certain triggers (eg alcohol, smoking, caffeine) might help. Stress is also a known factor that worsens bruxism, so preventing yourself from getting too tired is something you should actively remember, as this will reduce the occurrence.

Lastly seeing a sleep dentist might be a good idea to assess the impact of bruxism on tooth (eg tooth wear). Sleep dentists might also suggest some appliances to protect the teeth.

7. Question by Li Li

Dear doctor,

Thanks for the opportunity.

I grind my teeth during sleep. I also suffer from sudden severe nighttime muscle spasm/cramp during sleep which awakens me.

I also have trouble falling asleep a few days in a week.

May I know how the above can be treated?

Thanks in advance for your time and attention.

Answer by Clin Asst Prof Tushar

Dear Li Li,

Grinding of teeth or “Sleep bruxism” is seen in about 8% of adults. Most important aspect would be to ascertain that it is not secondary to another sleep disorder like obstructive sleep apnea (OSA); hence if you have additional symptoms like snoring, non-refreshing sleep or day time sleepiness, medical attention should be sought.

Simple measures like a good sleep hygiene, avoidance of certain triggers (eg alcohol, smoking, caffeine) should be considered if present. Stress may increase the occurrence of bruxism and stress relieving measures that suit you should be considered. Certain medications might help but usually not recommended for long-term use, considering the side effects and benefits. Lastly seeing a sleep dentist might be a good idea to assess the impact of bruxism on tooth (eg tooth wear). Sleep dentists might also suggest some appliances to protect the teeth.

With regards to your second question, painful muscle cramps in legs during sleep are not uncommon. These can be troublesome and affect your sleep quality if they are frequent. The causes can be electrolyte imbalances involving calcium/potassium or magnesium, dehydration, thyroid disorders and diabetes, lumbar spine disorders; but frequently, no clear cause is identified.

Lifestyle measures are helpful. These include leg muscle stretching exercises before going to bed and regular physical exercise may help to reduce the occurrence. Avoiding alcohol, caffeine and avoiding exercising in extreme heat or on hard concrete floors might also be useful. If these simple measures don’t work, medical attention should be sought for consideration of further evaluation and for treatment with medications.

With regards to your symptom of trouble falling asleep, if this is frequent enough (eg, more than three nights per week and for more than three months), this could be a symptom of insomnia. A good sleep hygiene is useful. Wind down your day slowly, dim the lights in preparation for sleep. Use the bed only for sleeping (no handphones or any other activity in bed). Avoid thinking while in bed. It is advisable to come out of bed if you cannot fall asleep in about 15 minutes, do some mild activity such as reading or listening music out of the bed and then go to bed again when you start feeling sleepy. Have a fixed wake up time. Also avoid caffeine for atleast 8 hours before your bed time. If you need a day time nap, a short nap earlier in the day is better than napping late in afternoon. Exercise and exposure to natural light in morning are also useful. If these sleep hygiene measures don’t help, and you continue to have difficulty falling asleep, leading to a feeling of tiredness in day time, you should consider seeing a sleep psychiatrist for further evaluation and treatment.

8. Question by Amanda

Dear Prof Tushar,

Age 58 going 59 years old. I do not smoke. I generally manage work stress well.

I do not drink water 2 hours before sleep to prevent waking up more than once to pee.

If I drink alcohol, it’s probably 2x a week with only 1-2 glasses.

I don’t eat carbs for dinner.

I tend to not be able to sleep on my back unless I am very, very tired. I am a restless sleeper.

My body has the bad habit of being a side sleeper but as I aged the blood circulation around my shoulder and numbness affects my sleep even more. Thus, I toss and turn a lot.

Also, once I am up in the middle of the night to pee it’s very difficult to go back to sleep. Thank you for your advice.

Answer by Clin Asst Prof Tushar

Hello Amanda

From what I understand, you don’t wake up more than once at night to pee with the precautions that you take. Waking up once at night to pass urine is considered acceptable.

I also don’t see that sleeping on one side is a problem as some people have that natural preference- but I also understand that this is causing you some symptoms now - like numbness.

I have a feeling that the restless sleep you describe (tossing and turning in bed) could be a primary issue. There could be few causes of restless sleep such as sleep apnea, periodic limb movements during sleep etc. It would be good to assess for these.

A sleep study can help to identify these problems if present. Also, I am not sure where exactly you feel the numbness- this might be important as numbness associated with conditions like carpal tunnel syndrome can be worse at night and can be treated effectively.

Inability to fall asleep again after waking up at night can be one symptom of insomnia; however, if this occurs once in a while, it might not be clinically significant, as many of us will have imperfect night sleep on an isolated occasion.

Overall there remain more questions than answers, and I think if your sleep is not refreshing and if you feel tired or sleepy during the day time, it would be good to see a sleep specialist who can try to pinpoint the issue and help in managing appropriately.

9. Question by Kareen

Dear Dr,

I go to bed about 11-11:30 pm and wakeup about 6:30 to 7 am. But my actual sleep is only 6 hours with awake time, whilst my deep sleep is very short, substantially is core sleep. The reading is from my watch on sleep score.

During the sleep duration I wake up about 2 times usually 3+ am to go toilet, or 4 or 5 am to sleep water but will try to go back to sleep.

Also, I do not have a deep sleep throughout the night, I feel in my sleep, my mind is not sleeping through the night.

How can I try to sleep well or what can help me to sleep better? Thank you for your advice.

Answer by Clin Asst Prof Tushar

Hello Kareen,

The recommended sleep for adults is about 7 to 8 hours. You seem to be spending enough time in bed, but you manage to sleep only 6 hours every night and you feel your mind is sort of “active” through the night. These symptoms might suggest a possibility of an insomnia-like problem. Having said so, smart watches have limitations in measuring sleep and may not be highly accurate in this respect.

There is no easy solution to this. But few important questions are-

Are you able to fall asleep easily?

Do you feel refreshed when you get out of bed in the morning?

Are you feeling tired throughout the day?

If you feel refreshed in the morning and don’t feel tired during the day time, then maybe you are still getting a good night's sleep despite the number of hours that are shown on the smart watch.

In general, a good sleep hygiene will help with the symptoms:

• Have fixed wake up time
• Use bed only to sleep, for example no handphones while in bed. Do not use the bed even for “thinking or worrying”.
• If unable to fall asleep or stay asleep, come out of bed. Don’t try “hard” to sleep when you cannot fall asleep easily, instead leave the bed and do some light activity like reading/ listening to music etc out of the bed until you feel sleepy again.
• Avoid stimulants such as caffeine atleast 8 hours before your bed time
• Exercise and have some sun exposure if possible in the morning.

If the above methods collectively fail to work and you are severely affected by the sleep disturbance, then it would be good to see a sleep specialist (probably a sleep- psychiatrist) who will assess your sleep in detail and may recommend you treatments like cognitive behavioural therapy or medications.

Lastly, it is always important to find out why you feel your sleep is light and why you wake up from sleep. Other sleep disorders causing frequent arousals from sleep such as sleep apnoea, should be ruled out if you have any suggestive symptoms like snoring or excessive day time sleepiness.

10. Question by C Yip

Dear Prof Tushar:

a) Why I have problem going back to sleep once I get up in the middle of the night?

b) Why my husband tends to have violent dreams (involving fighting) towards dawn when he is such a mild and peaceful person?

Answer by Clin Asst Prof Tushar

Hello C Yip,

Difficulty going back to sleep after getting up in the middle of night is not uncommon and may not signify anything serious if it happens occasionally. This is particularly common as one grows old. If severe (happening more than 3 days per week for more than 3 months) it might suggest an insomnia disorder.

If it occurs infrequently, one should avoid worrying about it, as such “worrying” might make the problem worse. An important question is whether you are getting the necessary 7 to 8 hours of sleep every night and whether you feel fresh (not sleepy) during the daytime. If the answer to these two questions is yes, then it is ok to have such bad nights intermittently.

But if you feel that your sleep disturbance is frequent and is affecting your daytime adversely, then it would be good to see a sleep psychiatrist, who may evaluate you further and suggest appropriate strategies to manage the insomnia symptoms.

With regards to your husband, the symptoms suggest that he has REM behavioural disorder (REM-BD). In this condition, people act out their dreams. The content of the dreams and the actions do not reflect the personality of the patient, and so I am not surprised if there are violent actions despite him being a peaceful and mild person.

In REM-BD, one does not have the normal muscle atonia (loss of muscle tone) which is expected to be present during the dream stage (REM stage) of sleep. As a result, one does the actions that correlate to their dream content. One may not be aware of the episode if not woken up, but if woken up during the event, one might recollect the dream.

REM- BD by itself may not always need medical treatment especially if mild and infrequent.

The risk is causing injuries to patient and partner.

Safety is important and one should keep the bedroom free of clutter and other potential hazards to minimize risk of injuries.  Remove all dangerous/ sharp, heavy or hard objects from the vicinity of the bed, apply soft padding on all the sharp or hard edges around the bed, ensure the windows are secure, use a low bed, and put a mattress or soft carpet on the floor. Bed partners being at risk of injuries from the actions of patients, appropriate measures should be taken to prevent this.

One may consider seeing a sleep neurologist, particularly if the symptoms are frequent and intense, or if they affect sleep significantly leading to daytime tiredness, as there are medications available that help to reduce these dream enactment episodes.

A good sleep hygiene in general is helpful.

Ref: F26