I started working as a graphic designer last year. Over the past couple of months I have had numbness and a tingling sensation in my right hand. It tends to be worse at night and often wakes me. Is my work causing this, and what can I do about it?
Conventional remedy
In Sweden, symptoms in the neck, shoulder, forearm and wrist have been called mouse- arm syndrome. The term attempts to link the occurrence of work-related upper limb disorders to increased use of the computer mouse in many occupations. It is estimated we use a mouse for 30 per cent of word-processing tasks, 40 per cent of spreadsheet tasks and up to 80 per cent of graphic-design tasks.
Although most such disorders develop slowly, the onset can be relatively quick.
Using a mouse as part of your occupation may have contributed to your condition. Using a mouse involves a number of features that can lead to upper limb problems. It is a repetitive task that research has shown we carry out more forcefully than we need to - perhaps because we are anxious about making mistakes.
We also put pressure on our tendons and nerves by resting our hands on the edge of a desk or keyboard, which adds to the problem. And being in stressful postures, such as deviating, flexing or hyperextending our wrists and reaching excessively, are all potential causes of repetitive strain injury in computer users.
Speak to your employer about your workstation, which may need to be modified to minimise the possibility of muscle overuse. Your working patterns should also be analysed, to identify repetitiveness, forcefulness and awkward postures, which will exacerbate your symptoms.
The symptoms you describe may be caused by pressure on the median nerve as it travels through the carpal tunnel, which is made up of the carpal bones in the wrist and a tough membrane. Within the carpal tunnel are many tendons, nerves and arteries, all within a confined space.
Your doctor will be able to diagnose the problem by your description of the symptoms and, in particular, if you give him an accurate account of the type of work you do. He will then assess the range of motion at your wrist, elbow and shoulder joints, and he will ask you to carry out certain manoeuvres of the hand.
You may require further evaluation, such as an electromyograph, which measures the speed at which signals travel down the nerve.
Treatment with anti-inflammatory drugs is a very useful first-line treatment. Drugs such as Brufen, Voltarol and Ponstan act as both painkillers and anti-inflammatories. Do not use them to work through pain, however, as this may only cause long-term, irreversible problems. Local injection of steroid or anaesthetic may also help in some cases, as will physiotherapy.
There are tips you can follow to help avoid repetitive strain injury, especially if your work involves the use of a computer mouse. Take regular breaks, vary the tasks you do and carry out simple stretching exercises of your fingers, wrist and neck at your workstation. Try not to lean your wrists against the hard edges of the keyboard, arrange your workstation so the hand and wrist using the mouse are not bent and tune the mouse response - the time delay between clicks - to suit your work habits.
Muiris Houston
Alternative remedy
Sensations such as tingling and numbness, or paraesthesia, are common transient phenomena when peripheral nerves are stretched or subjected to pressure.
The most likely explanation for the symptoms is that nerves at the base of the neck are being impinged. Body tissues are normally warm and mobile during the day. At night, they cool down as they move less, giving way to more irritation.
Further discomfort can be caused by poor posture, such as sleeping on the stomach or using unsupportive pillows. Both of these can stretch and irritate nerves at the base of the neck.
Another possibility is carpal tunnel syndrome brought on by overuse of the right hand, thus irritating the nerves locally. Symptoms that wake a patient at night can suggest something more complicated and may require investigation.
Questions an osteopath might ask include whether you have any previous neck injuries, such as whiplash; if you have lost muscle strength or power or experience pain or discomfort when you move your head. These help to ascertain the severity of the nerve entrapment.
The treatment would involve working directly on the wrist, to reduce pressure on the nerves. Massage-like techniques will reduce muscle spasm.
Articulation and manipulation will improve movement and release entrapped nerve roots. A complete examination by an osteopath takes into account the structure and function of the whole body.
Also, I would suggest exercises to help stretch and strengthen the neck and wrist. Sit in a proper posture at work - lift your breast bone when sitting and, when talking to colleagues, turn your whole body towards them.
Alexander Gibbs, registered osteopath
The Irish Osteopath Association is at 01-2695281