Around half of people who have a stroke will experience swallowing difficulties. Figures on incidence vary by type of stroke, with incidence highest in brainstem stroke. In medical notes, swallowing difficulties are referred to as dysphagia. It is caused by damage to the cranial nerves which may affect movement and sensation in the mouth and throat. Coughing or choking on food or drink are the most obvious signs of dysphagia.
The body produces a cough in response to any foreign body entering the airway as a protective mechanism to expel it and protect the lungs. Many people don’t believe they have a swallowing difficulty unless they are coughing on food or drink, but the cough is a sensory response, so if sensation is affected, it is possible for food and drink to be entering the lungs without triggering a cough.
In these cases the first sign that something is wrong is often the person developing a chest infection. If food or drink enters the lungs, there is a high risk that a chest infection will follow. A ‘wet’ sounding voice is also a common sign that food or drink has entered the airway and is pooling around the vocal folds. Facial weakness is common in strokes, so food spilling out of the mouth or collecting in cheek cavities can cause problems. If the soft palate doesn’t seal off, the nasal cavity during swallowing, food can come down the nose.
Early assessment of swallowing after a stroke is vital; the Royal College of Physicians’ clinical guideline is that acute stroke patients must have their swallow assessed within four hours of admission and may not have anything to eat or drink or even take medication orally until this has been done. If not managed successfully, patients with dysphagia have a higher morbidity rate and are at high risk of a longer hospital stay, chest infection, malnutrition and asphyxia by choking. Initial screening will usually involve being given small amounts of water. If this is swallowed successfully it will be followed by some smooth yoghurt and if this causes no problems, the final test is a plain biscuit. Get a plain digestive down with a speech therapist watching closely while you chew and feeling your neck to see if your larynx moves — no water allowed to help it along — and you are deemed safe to manage a normal diet.
If difficulties are identified at any stage of this screening, a plan will be put in place to help you manage and ideally rehabilitate your swallow. If there is evidence that you have moderate or severe difficulties, have repeated chest infections or are silently aspirating (food entering the lungs with no cough response), you may be referred for a videofluoroscopy. This is a moving X-ray of your swallow, which is filmed and then slowed down and analysed frame by frame so that your speech therapist can work out exactly where the difficulties are happening and why. Slowing the film is necessary because the many and complex movements that make up the swallow are completed in less than a second.
The prognosis for people with dysphagia post-stroke is usually good; for the majority, swallow function will recover completely, usually in the first few months after the stroke. If difficulties are severe, tube feeding may be necessary, usually via the nose, for a short period. Once oral feeding is re-established, management strategies can be used to protect and rehabilitate swallowing. Sometimes a change in position and rate of eating is sufficient to protect the swallow. Sitting up straight, deliberately slowing your rate of eating and avoiding over-large mouthfuls are an excellent start. A chin tuck manoeuvre may be advised as this naturally improves protection of the airway while swallowing. In some cases, turning your head towards the affected side before swallowing can help by closing off the weaker side of the throat. The moves are simple but need to be done for every single mouthful, so are not suitable if the patient has memory difficulties. A modified diet may be prescribed, with food textures altered to be easier and safer to swallow. Modifications range from puréeing of all foods at the more severe end, to simply following a soft diet.
If it is fluids that are causing problems, a common solution is to prescribe thickeners to be added to drinks. Thickening liquids slows down transit through the throat and gives the body more time to engage the protective reflexes used in swallowing. Thickeners are widely used and can be effective but they are not popular with patients. There are two types available. One is made with cornstarch and the other with xanthan gum (check the label). Many people find that the xanthan gum-based thickeners are more palatable as they have a gel-like consistency. Cornstarch thickeners have a texture more akin to — I cannot lie — wallpaper paste. Having tested both extensively I know which I would want. They cost the same, so your GP should be able to prescribe whichever you prefer.
Some drinks are more acceptable thickened than others — squash and juice are nicer than water and the consensus on hot drinks is that thickened milky drinks like hot chocolate taste better than thickened tea. Most people will only need thickened drinks for a short time after the stroke. Exercise programmes can be used to strengthen the muscles used in swallowing. Some oral motor exercises are relatively simple; you will more than likely be required to spend some time in front of a mirror pulling faces — this needs to happen frequently to make a difference.
Others that work on harder-to-reach muscles can seem quite strange. For example, one widely used exercise for strengthening the tongue base muscle (crucial for generating enough pressure to push food down into the throat) involves sticking your tongue out, holding it between your teeth and swallowing repeatedly. It’s important to stick to the exercises advised by your therapist as strengthening the wrong muscles can make your swallow worse.
A relatively recent development in swallow rehabilitation is the use of Neuromuscular Stimulation (NMES); electrodes used to stimulate the muscles used in swallowing. The approach has a good evidence base in physiotherapy, but some controversy surrounds its use with swallow because the swallow is a reflex rather than a voluntary movement. Clinical trials are under way at the moment.
I have tried NMES on the receiving end and can say that while it feels decidedly odd — on one occasion it made me jump out of my seat — it really is painless. Sensation (smell, taste, temperature, feel of food in the mouth) is as important to a healthy swallow as motor movement; without adequate sensory feedback, the swallow reflex may be slow to trigger or fail to trigger at all. This means food or drink can enter the throat before the airway is sealed off and may penetrate into the airway. With reduced sensation, people may also be unable to detect or manipulate food and drink in the mouth, causing food to lodge in cheek cavities, or spill into the throat before they are ready to swallow.
Sensory impairment of swallow can be hard to treat, but altering taste, texture and temperature can all help stimulate the swallow reflex. If the damage to your swallow is severe and not responding to rehabilitation, it may be necessary to consider longer term non-oral nutrition. This is done via a PEG (Percutaneous Gastrostomy) tube into the stomach. Having a PEG doesn’t necessarily mean that there is no way back to oral feeding. Sometimes a PEG is sited for a period of months so that adequate nutrition and hydration can be maintained while the swallow is rehabilitated. This will be closely monitored and oral feeding can be slowly reintroduced as the swallow improves.