MDC Publication Highlights - August 2018
17 September 2018
MDC recent publication highlights (August 2018): Young onset MSA, how to predict dementia in Parkinson's, parkinsonism following DBS in dystonia and new insight into Parkinson's pathphysiology
Young-onset multiple system atrophy: Clinical and pathological features
Mutiple system atrophy (MSA) is a rare neurological condition that is caused by degeneration (atrophy) of nerve cells in multiple areas of the brain. While symptoms usually become apparent in people aged 50 to 60, “young-onset MSA” (YOMSA) can be seen in people under 40 years of age. MSA patients are often misdiagnosed, especially in the early stages of their disease, mainly because the condition appears very similar to Parkinson’s disease and its underlying cause is poorly understood.
As the first study of its kind, Professor Kailash Bhatia and colleagues identified key features of YOMSA, both clinically and pathologically, successfully highlighting useful differences between YOMSA and Parkinson’s. The researchers suggest that in young patients with parkinsonism symptoms, the presence of impaired muscle tone (dystonia), shock-like contractions (myoclonus) and pyramidal signs, might serve as diagnostic clues for YOMSA.
- Batla et al. ‘Young‐onset multiple system atrophy: Clinical and pathological features'. Movement Disorders, First published: 28 August 2018. https://doi.org/10.1002/mds.27450
Parkinsonian signs in patients with cervical dystonia treated with pallidal deep brain stimulation
Deep brain stimulation (DBS) has been established as an effective and safe treatment for patients with dystonia for more than a decade. However, anecdotal evidence suggested that some dystonia patients might develop certain parkinsonian symptoms following DBS. In the current study, MDC researchers led by Professor Patricia Limousin evaluated parkinsonian symptoms and their relevance to daily motor functioning and quality of life in patients with dystonia, comparing patients treated with DBS to those treated with conservative treatment options (without DBS).
The researchers found that while mild Parkinsonian symptoms were observed in many dystonia patients, they were more severe in patients treated with DBS. The most prominent Parkinsonian symptoms observed in DBS-treated dystonia patients were problems of gait and posture and general slowness of movement (bradykinesia). The researchers found that while Parkinsonian symptoms generally had a negative effect on patients’ quality of live, dystonia patients treated by DBS were nonetheless faring better than patients treated conservatively. Given the overall positive effects of DBS in dystonia patients, the researchers suggest that the increased risk of Parkinsonian symptoms should not influence the decision of choosing this treatment option. Rather, dystonia patients with DBS should be monitored more closely and specifically for features of Parkinsonism, both in clinical routine and future clinical trials.
- Mahlknecht et al. 'Parkinsonian signs in patients with cervical dystonia treated with pallidal deep brain stimulation'. Brain, First published: 24 August 2018. https://doi.org/10.1093/brain/awy217
Can neuroimaging predict dementia in Parkinson’s disease?
While severity and timing varies, as many as 50% of people with Parkinson’s are affected by dementia within 10 years of diagnosis. This significant statistic emphasises the need for a robust prediction mechanism, not only to provide essential prognostic information to patients, but also to identify at-risk individuals for clinical trials of potential disease-modifying treatments as well as to help explain the underlying causes of the disease itself.
Neuroimaging has made little contribution to predicting cognitive involvement in Parkinson’s disease to date. In this review paper, MDC researchers led by Dr Rimona Weil demonstrate how emerging imaging technologies with much higher sensitivity are likely to detect certain changes in the brain that might reflect early signs of cognitive impairment. The researchers highlight the need to employ such techniques in large-scale collaborative imaging initiatives.
- Lanskey et al. 'Can neuroimaging predict dementia in Parkinson’s disease?'. Brain, Volume 141, Issue 9, 1 September 2018. https://doi.org/10.1093/brain/awy211
Modulation of beta bursts in the subthalamic nucleus predicts motor performance
‘Beta waves’ are neural oscillations (brainwaves) within a specific range of frequency. Exaggerated forms of this brain activity are often seen in the subthalamic nucleus of the basal ganglia in patients with Parkinson’s disease. This heightened activity is not continuous but in fact fluctuates to give ‘beta bursts’ and can be suppressed by dopaminergic treatment such as levodopa. It has been seen that prolonged and increased probability of these bursts correlates with the severity of motor impairment in Parkinson’s and the degree of suppression through treatment correlates with an improvement of motor performance.
In the present study, the researchers test the hypothesis that beta bursts may help explain spontaneous variations in motor behaviour, using local field potential recordings taken from the brains of treated Parkinson’s patients with drug-normalised motor behaviour. Results of the study suggest that modulation of the timing and amplitude of beta bursts might serve to dynamically adapt motor performance, therefore offering new insight into the pathology Parkinson’s disease.
- Torrecilloa et al. 'Modulation of beta bursts in the subthalamic nucleus predicts motor performance'. Journal of Neuroscience, First published: 4 September 2018. https://doi.org/10.1523/JNEUROSCI.1314-18.2018