Frequently Asked Questions

An electrical current passes through the leads (electrodes) within the brain, and this has the effect of modulating some of the neural pathways in the brain that are involved in movement disorders. Depending on the exact location of the electrodes, this effect can significantly improve symptoms. However the stimulation can also affect other nearby pathways, and this can sometimes produce side-effects. While there are some exceptions, in general DBS is reversible; when the electrical current is switched off, the effect on symptoms, or side-effects, will disappear.

We initially receive a referral from your specialist, following which you will go on a waiting list to be seen at our new patient clinic. If DBS is felt to be a possible treatment option for you, a series of further investigations are organised. Currently it takes around 18 months to 2 years from first referral to surgery and we are working to reduce this time frame.

The neuropsychology team have a crucial role in assessing patients for DBS suitability. They carry out a detailed assessment of cognition, thinking, and memory. We recognise that many movement disorders will either cause, or be associated with, thinking and memory problems. It is essential that we identify any issues before making a decision to proceed with surgery. Occasionally we identify significant or severe problems which can mean DBS is not a suitable treatment option. More often, we identify mild problems which are not a barrier to surgery, but increase the risk of more significant thinking and memory difficulties postoperatively. It is vital to be aware of this risk so patients can be counselled appropriately before agreeing to go ahead with surgery.

The levodopa challenge is part of the pre-DBS assessment process specifically in Parkinson’s disease, and tends to be the best predictor of whether DBS is suitable for you. It involves first assessing your condition in the OFF state (when medications are not working, and you are usually slow and stiff, possibly with more tremor). This is done by stopping your usual Parkinson’s medications on the morning of the test. Depending on your symptoms and how far away from Glasgow you live, this sometimes means an overnight stay in hospital. We then assess your symptoms in the ON state, by giving you a large dose of dopamine (levodopa). In general we are looking for at least a 40% improvement in your symptoms between the OFF and ON state.

The exact method of surgery depends on many factors, including your diagnosis, other health conditions, and the target within the brain we are aiming for. This will be discussed with you in great detail. Most of our procedures are now performed asleep however we do still carry out some procedures “awake”, usually to monitor the effectiveness of the electrodes in improving tremor, or slowness, and stiffness wherein selected cases we feel this gives us helpful feedback.

In reality this is done under “conscious sedation”, where a drug called dexmedetomidine is administered that tends to cause patients to fall into a light doze, where they are only vaguely aware of what is going on around them. Local anaesthetic is applied to the scalp so that no pain is felt from the operation sites. At the time of electrode implantation, the drug is stopped so we can assess the effect of stimulation on symptoms.

For some patients, this kind of surgery is not suitable and the operation is done “asleep”, under general anaesthetic. Patient choice is the most important factor; we will not insist on “awake” surgery if you do not want it.

We would usually trim a small amount of hair close to the wounds, but you do not need your whole head shaved. You can discuss this further with your surgeon.

DBS in general is a very safe operation, and the vast majority of patients undergoing surgery in Glasgow have no problems. However it remains major surgery, and does carry a number of rare, but serious risks. Infection is one of the most common of all surgical complications, and is a particular worry in DBS; if serious infection settles onto the DBS implants, they need to be removed, and replaced at a later date. Thankfully this is very rare. There is a very small risk of bleeding inside the brain from placing the electrode; this can be very serious if it does happen, potentially causing a stroke, or even a threat to life. However even when bleeding does occur, it tends to cause milder and temporary symptoms. There is a small risk of seizures or fits following surgery, but again this is rare. The DVLA forbid driving immediately following surgery, but standard car licence holders can usually restart around 6 weeks postoperatively if all is well. There is a small risk of the electrodes being suboptimally placed during surgery resulting in a poor response; this is also rare, but can result in further surgery to improve the electrode position. Lastly the stimulation itself can cause side-effects such as tingling, numbness, muscle effects, speech problems, and balance problems; however these are usually reversible by turning down or switching off the stimulation.

In DBS systems there are rechargeable (RC), and non-rechargeable or “primary cell” (PC) batteries. Rechargeable batteries tend to be smaller, and last much longer before needing to be replaced, typically 10-25 years. However they also need to recharged via a surface recharging device. The amount of recharging varies hugely, but is typically 1-2 hours, 1-2 times per week. They tend to be a good option for younger patients, or “high energy users”, who would otherwise require many battery changes over their lifetime.

Primary cell batteries are a little bigger, and tend to last 3-5 years before needing to be replaced. This is done via a small, usually daycase operation. They do not need much attention once in place and working, and tend to be a good option for patients who don’t want to think about their DBS system too much, or who would find recharging overly difficult.

You can find more information in the section on manufacturers.

We recommend avoiding submerging your wounds in water (such as a bath or swimming pool) for four weeks postoperatively, until the incisions are completely healed. In general swimming after DBS is possible. However a small number of patients with Parkinson’s disease have experienced difficulty with swimming after DBS surgery. While this is rare, we recommend that when starting to swim again after DBS surgery, you do so in a safe environment such as a shallow pool with other people nearby, and avoid unsupervised or deep water swimming.

MR-guided focused ultrasound (MRgFUS) is a different surgical technique currently used to treat essential tremor. In Scotland, this is delivered from the MRgFUS centre at Ninewells Hospital in Dundee. At the moment it is not available for the treatment of tremor in Parkinson’s disease, or dystonia. The Glasgow DBS team have a close relationship with the Dundee MRgFUS team, and often discuss patients who may benefit from either treatment. Where possible we try to direct patients to the centre providing the treatment we think will be of most benefit. However many of our assessments are similar, and some patients do cross from one pathway to another.

More information on MRgFUS is available here.

The DBS team aims to decide whether DBS is the right treatment option for you and your condition. Some patients will not benefit from DBS, and this will be discussed with you, and your referring specialist and GP will be informed in detail. For some conditions there may be other therapies available that may be more appropriate for you. While it is not usually our role to advise you on other, non-DBS options, occasionally patients or referring doctors will ask us to discuss this.

After your operation we advise that you do not drive for at least 6 weeks. DVLA rules and regulations are frequently updated so we advise you to check this with the DVLA at www.gov.uk/driving-medical-conditions; (look under implanted electrodes or deep brain stimulation for movement disorder or pain).

After the operation you should not have a MRI scan without discussing this with the DBS team. It is often possible to have a MRI scan with certain precautions.

You may need a surgical procedure sometime in the future after your DBS operation (such as a joint replacement or spinal surgery). Your surgical team will need to know that you have a DBS device implanted before performing surgery, and may need to take some precautions (such as turning off the device). We advise you to have prophylactic antibiotics for surgery as would be normal routine practice.

Non-emergency dental work should be delayed for 3 months following implantation or battery change to avoid possible implant infection via the blood. If dental work is required within the first 3 months, then we would advise oral antibiotic prophylaxis. Thereafter antibiotic cover for dental work is not routinely required but may be justified in selected high-risk cases (examples could include periodontal surgery or if you are diabetic or if your immune system is compromised), your dental practitioner can contact us for advice in these cases

Diathermy (also known as electrocautery) is when an electric current is used to heat body tissues during surgery in order to seal blood vessels. If possible, only bipolar diathermy should be used in operations. However if only monopolar is available then the high voltage mode should be avoided. The power setting should be kept as low as possible and the ground plate should be kept as far away from the neurostimulator, extension and leads as possible.

Other devices or equipment to avoid

The devices that may cause problems with your DBS system usually will contain strong magnets. Anything that may have a strong magnet within it should not come in close proximity to your IPG (battery).

1. Security screening devices, such as in airports (those found at the exits from shops are fine). When approaching them, hand over your patient identification card, explain you have a "brain pacemaker", and request a search by hand.
2. Induction devices (induction hobs for cooking, induction charging devices). These can be used, but it is sensible to avoid your battery coming close to the device (ideally keep more than 30cm away).
3. Charging devices for electric or hybrid vehicles. Again these can be used, but keep them at least 30cm away from your battery.
4. Some modern mobile phones contain magnets for induction charging. These can be used, but keep at least 30cm away from your battery and avoid putting them in a breast pocket, for example.

Other tests or scans

X-rays, CT scans and PET scans are not likely to affect the DBS system.

Devices that you can operate without any problem

Computers, copiers, faxes, electric blankets, heating pads, washing machines, dryers, garage door openers, electric stoves, vacuum cleaners, hair dryers, shavers, remote controls, toasters, blenders, electric can openers, food processors, microwave ovens, televisions, radios, video recorders, CD players, mobile phone and tablets.

After the surgical scars are healed (usually at least 6 weeks) you can return to most physical activities except for those that result in repeated blows to the device such as boxing. You should always wear a helmet for sports such as cycling, skiing, snowboarding and horse riding. You should avoid parachute jumping and skydiving.

You should not fly until 6 weeks after the operation.

You should attend any breast screening that you are invited to and tell the radiographer when you attend who should be familiar with what to do. Depending on the position of the DBS battery (implantable pulse generator), it may be difficult to X-ray the entire breast and sometimes only a partial mammogram is possible. Taking the X-rays will involve some pressure on the device, but this would be kept to a minimum.