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What is swallowing?

Swallowing is a very complex mechanism. It begins with the sight of food and the subsequent production of saliva. Food is taken into the mouth, chewed, rolled into a ball and finally swallowed, that is, pushed through the throat and into the oesophagus and eventually down to the stomach. The actual swallow reflex is triggered by food touching the back of the mouth and is normally an involuntary action when eating.

Swallowing and eating difficulties - known as dysphagia - occur in many other medical conditions and as part of the normal ageing process, but it is particularly common for people with Parkinson’s to be affected. This is because swallowing is a motor function. 


How might Parkinson’s affect swallowing and eating?

Most people with Parkinson’s experience dysphagia due to the reduced control they have of their mouth and throat muscles, especially in the later stages of the condition. Eating becomes slower, more hesitant and requires more effort. It can become increasingly difficult to clear the mouth of saliva, and to swallow instinctively when muscles become weak or rigid.

A weakening of the lips, tongue and jaw muscles means that chewing becomes difficult and makes it hard to seal the lips tightly. Being unable to close the lips tightly makes it difficult for anyone to swallow, and means that food or drink can spill out of the mouth when eating or drooling may occur as saliva is not swallowed.

Saliva should be swallowed automatically, but this mechanism can be disrupted in Parkinson’s. Normally we produce about a litre of saliva each day, but if this increases or decreases swallowing can be difficult. Dribbling or drooling may result if saliva is allowed to build up in the mouth. To clear saliva the following tips may be helpful:

  • drink more frequently so saliva is ‘washed down’ with fluids
  • swallow saliva often, making a conscious effort to do so before eating
  • keep your head up so that saliva more naturally flows to the back of your throat to make swallowing easier.
Some people find they get an increase in mucous from dairy products. It may therefore be worth trying reducing dairy in your diet. However this needs to be balanced with the fact that milk provides calcium and other nutrients, which are beneficial.

In contrast, some people with Parkinson's suffer with a dry mouth because they swallow repetitively which uses up the saliva that is needed for comfortably swallowing food and smoothly moving it through the throat. This lack of lubrication can result in a sore, rough or dry throat making talking uncomfortable. Dry mouth may also be caused by some Parkinson’s medications, particularly anticholinergic medications. People with dry mouths could try taking frequent sips of water, sucking on ice chips or using a mouth spray. Caffeine, soft drinks, alcohol and tobacco, which all dry the mouth, should also be avoided.

Some people find Parkinson’s medications can cause tastes to alter. Often food tastes metallic and unappetising and the production of saliva may be reduced. This not only exacerbates the problem of dry mouth and swallowing, but also the important enzymes in saliva that begin to break down food are no longer present.

Also, with Parkinson’s, it is common for the tongue to bunch up, forcing food to be pushed out through the mouth or teeth rather than be swallowed.

Impaired coordination may reduce the ability to move food around the mouth when eating, so passing it from side to side in order to chew becomes difficult and the process of eating is long and tiring. Some food may also remain in the mouth and if unnoticed, as often happens with Parkinson’s, the risks of choking and infections are greater.

Dental changes may also occur and these combined with motor problems can make chewing food very uncomfortable or difficult.

Parkinson’s can also affect the muscles that carry food to the stomach once swallowed. This process may become much slower causing a sensation of being full even though not much food has been eaten. Only when food reaches the stomach does a feeling of being hungry return. It is therefore crucial that time is given to eat.

If eating is difficult and tiring, and food becomes unappetising due to the effects of Parkinson's medications or reduced confidence in eating, food intake is likely to drop and this may result in weight loss. It is important to maintain a reasonable intake of food for your height and build and to keep a healthy weight so as to fight infection and generally stay well.

Finally, dysphagia can cause embarrassment. Eating should be an enjoyable social activity, but it is often something that is avoided in company. Fear of choking can add stress when eating and panic attacks are not uncommon before mealtimes. Dysphagia can therefore have a very negative impact on quality of life. It is important that your family, Carer and friends understand why you have problems with eating and that it is often part of life with Parkinson’s. If they know how to support you and give you more time when eating this should help you to enjoy meals and continue to do so in a social setting.


Did you know?

According to the Department of Gastroenterology at the Cleveland Clinic (USA) the total phase of swallowing, from mouth to stomach, takes seven to nine seconds.


The dangers of dysphagia

It is very important that any swallowing problems are closely monitored so that eating is as safe as possible. The main risks associated with swallowing problems are:

  • asphyxiation - food blocks the airway and breathing stops
  • Aspiration pneumonia – food or liquid enters the lungs rather than the stomach and causes a lung infection. This may be ‘silent aspiration’, that is there is no cough and food passes through unchecked
  • dehydration – insufficient fluid intake leads to other symptoms, for example Constipation
  • malnutrition – insufficient food intake leads to reduced levels of general health so quality of life and the ability to fight infections is compromised.

If you notice any problems with eating and swallowing, either in yourself or in someone you care for, it is important to discuss these with a doctor. Warning signs to look out for are:

  • hesitation in swallowing or an inability to start the swallowing process
  • food sticking in the throat or left in the mouth after meals
  • choking
  • a repeated need to swallow in order to clear food
  • swallowed food backs up and enter the nose
  • difficulty chewing
  • food regurgitation
  • coughing during or after swallowing
  • frequent throat clearing or a hoarse voice
  • a ‘gurgly’ voice or sore throat
  • discomfort in the throat or chest
  • reflux or Heartburn
  • a need to frequently sip water in order to swallow food
  • taking a long time to finish a meal, or giving up part way through
  • loss of appetite or refusal to eat
  • unexplained weight loss
  • dehydration
  • recurring chest infections.

Swallowing and medication

If swallowing tablets or capsules is difficult it may be tempting to crush tablets or open capsules but you should never do this without first checking that this is safe. This is usually stated in the patient information leaflet (PIL) or you can check with your pharmacist or doctor.If a medicine has not been tested for use in this way it may cause serious side effects, or it may mean that it does not work properly and so may not provide effective treatment. 

Many medicines have been formulated to work in a particular manner or are prepared in a certain way for specific reasons.  For example:

  • sugar or film coated – this is usually to make a medication taste better, but crushing may make it taste very unpleasant
  • enteric coating - this coating is designed to keep the tablet whole in the stomach, in some cases to protect the stomach or to protect the medicine from the stomach's acid so that it is released after the stomach, for example in the intestine.  This type of tablet should never be crushed as this will destroy the enteric coating
  • modified or controlled release - this means that a medication has been designed to release slowly so that it acts over a longer period and does not need to be taken as often.  This type of tablet should never be crushed as this leads a rapid release of the medicine which can be harmful and will not allow it to work as intended.
If swallowing is difficult then you should talk with your doctor so that they can prescribe medication in a form that is easier for you to take.  Some are available in liquid form.

Did you know?

The scientific community use the term ‘deglutition’ rather than ‘swallow’.

Acknowledgement

We would like to thank the following for their contributions to this information:

  • Julia Johnson, Speech and language therapist, Regional Neurosciences Centre, King’s College Hospital, London & Clinical Advisor on Progressive Neurological Disease, Royal College of Speech and Language Therapists, London

We would like to acknowledge the following source(s) in compiling this information:

  • Eating, swallowing and saliva control in Parkinson’s, Parkinson's UK
  • Parkinson’s and swallowing, Parkinson’s New Zealand