For many Parkinson’s disease sufferers, the side effects of their medication can be just as troublesome as the symptoms they are treating. At ClearSky Medical Diagnostics in York, researchers have been using evolutionary algorithms to develop as set of electronic devices which monitor these side effects, with the potential to greatly improve patients’ quality of life.
By Lily Clarke
Parkinson’s disease is a degenerative neurological disease, which occurs due to the loss of nerve cells that produce a chemical called dopamine. Dopamine helps the brain with regulating emotional responses and movement, and so dopamine deficiency in Parkinson’s patients can cause tremor, muscle stiffness (akinesia) and slow movements (bradykinesia). Although there is a wealth of medication available to manage these symptoms, many of these bring along unpleasant side effects that have proven difficult to control.
Levodopa is one of the most effective drugs for treating Parkinson’s disease. Despite this, many of its users experience regular involuntary movements, known as levodopa-induced dyskinesia (or LID), that can drastically hinder their quality of life.
Not all patients experience LID, but the risk is increased by a younger age of disease onset, higher severity of their disease, and higher dosage of levodopa. LID occurs when levodopa levels are at their peak or when the levels are changing quickly, and so it can be managed by careful tweaking of the patient’s medication schedule. However, this has so far been challenging. Clinicians currently rely purely on the patient reporting when they took their medication and when they experienced involuntary movements. This can be unreliable: LID can occur at night or be too minor to notice, or patients may not remember due to cognitive impairment (another symptom of Parkinson’s).
At ClearSky Medical Diagnostics, a company associated with the University of York’s Department of Electronics, researchers have been working on a device which will more accurately show nurses when patients are experiencing LID. Nurses will be able to see how this relates to when medication was taken, so they can make fine alterations to the patient’s medication schedule. Known as the LID-Monitor, the device should ultimately be able to help patients minimise their involuntary movements through careful control of their medication schedules.
The LID-Monitor is made up of six small, wireless electronic devices worn on the patient’s head, torso, arms and legs. All the patient has to do is wear the unobtrusive devices for a 24-hour period and keep to their ordinary medication schedule throughout this time. At the end of the session, the data from the devices can be used to see when the patient experienced involuntary movements in relation to when they took their medication.
It sounds simple enough, but there’s some fascinating technology going on behind the scenes. Each device contains an accelerometer, which is constantly taking time-stamped measurements of the wearer’s motion. Once the session is finished, the accelerometer data is run through a classifier, developed by training evolutionary algorithms to differentiate between voluntary and involuntary movements. For each 10 minute block, the classifier produces a number between zero and four, representing the severity of the dyskinesia according to the Unified Dyskinesia Rating Scale. After all of the data has been classified, graph-plotting software is used to produce an easy-to-read clock-face graph.
The benefits are numerous. Results produced by the LID-Monitor are far more accurate than just relying on patients to report back to their clinician about their symptoms, and so the patient’s medication schedule can be tweaked much more effectively. Because the session can take place at home with the patient carrying out their normal daily routine, it also eliminates the need for patients to have extended hospital stays to monitor the symptoms. The LID-Monitor also makes it easy to track patients’ progress. The session can be repeated at regular intervals and the results compared to directly see if the medication alterations are having the desired effect.