A group of experts working under the umbrella of the International Parkinson and Movement Disorder Society (MDS), have developed a new tool for healthcare professionals that they hope will mark a significant advancement in the diagnosis and treatment of Parkinson’s disease, especially in its early stages.
The results of their study, published in the journal Movement Disorders, could also have a major impact on the quality of research on Parkinson’s disease.
Parkinson’s disease (PD) is a neurological condition related to the death of specifi brain cells, including cells that control movement, mood, sleep and cognition. The symptoms, which include tremors, slowness of movement, stiffness or rigidity, sleep disorders, loss of the sense of smell, depression, and cognitive dysfunction, can appear in people as young as their thirties, but more commonly appear around the age of 60. It is estimated that the disease touches more than one in 50 people in this age group.
Currently, diagnosis of PD can only be established through an analysis of medical history and a neurological examination by a clinician with expertise in movement disorders – no objective test for the disease exists. As the symptoms of PD often resemble those of other neurological disorders, the rate of misdiagnosis can be as high as 25 per cent, which causes distress in patients. It also creates a challenge for researchers as the data collected in clinical studies can become compromised by misdiagnosis in their pool of subjects.
Comprehensive criteria to aid diagnosis
The new criteria gathered knowledge and data from movement disorder experts around the world to create the most comprehensive diagnostic criteria ever developed for the disease, with the aim of improving and broadening diagnosis and treatment of the disease, especially in the early stages.
“In light of the latest scientific insights and technological advances, we were able to establish a new list of criteria based on expert clinical diagnosis,” says Dr. Ron Postuma, co-Chair of the MDS task force, who is also a researcher in neurosciences at the Research Institute of the McGill University Health Centre and at The Neuro, and associate professor in the Department of Neurology and Neurosurgery at McGill University. “Our aim was to create a benchmark that will systematize the diagnostic process, make it reproducible across centers and that will enable a wider range of non PD-specialized clinicians to provide patients with an accurate diagnosis.”
“These criteria accent how Parkinson’s disease is much more than a simple motor disorder, now incorporating motor and non-motor symptoms as well as the genetic component in some forms of PD,” adds Dr. Daniela Berg, Chair of the MDS task force and Associate Professor at the University of Tübingen, Germany.
New stage classification proposed
The research team is proposing a new stage classification of the disorder with the aim of focusing attention on the early stages of PD. “With this new classification our goal is to set up a research agenda that will help identify the features that signal the presence of the disease early on,” explains Dr. Postuma. “Our hope is that, as research advances, our understanding of the mechanisms at play in the disorder will enable us to develop therapies and treatments that can be administered early in this process, eventually slowing or stopping the progression of PD altogether.”
An estimated 100,000 Canadians live with PD. Although some drugs and clinical treatments can help control or minimize symptoms there is currently no cure.
Source: Julie Robert – McGill University
Image Credit: The image is adapted from the McGill press release
Original Research: Full open access research for “MDS clinical diagnostic criteria for Parkinson’s disease” by Ronald B. Postuma MD, MSc, Daniela Berg MD, Matthew Stern MD, Werner Poewe MD, C. Warren Olanow MD, FRCPC, Wolfgang Oertel MD, José Obeso MD, PhD, Kenneth Marek MD, Irene Litvan MD, Anthony E. Lang OC, MD, FRCPC, Glenda Halliday PhD, Christopher G. Goetz MD, Thomas Gasser MD, Bruno Dubois MD, PhD, Piu Chan MD, PhD, Bastiaan R. Bloem MD, PhD, Charles H. Adler MD, PhD and Günther Deuschl MD in Movement Disorders. Published online October 16 2015 doi:10.1002/mds.26424
Abstract for “MDS research criteria for prodromal Parkinson’s disease” by Daniela Berg MD, Ronald B. Postuma MD, MSc, Charles H. Adler MD, PhD, Bastiaan R. Bloem MD, PhD, Piu Chan MD, PhD, Bruno Dubois MD, PhD, Thomas Gasser MD, Christopher G. Goetz MD, Glenda Halliday PhD, Lawrence Joseph PhD, Anthony E. Lang OC, MD, FRCPC, Inga Liepelt-Scarfone PhD, Irene Litvan MD, Kenneth Marek MD, José Obeso MD, PhD, Wolfgang Oertel MD, C. Warren Olanow MD, FRCPC, Werner Poewe MD, Matthew Stern MD and Günther Deuschl MD in Movement Disorders. Published online October 16 2015 doi:10.1002/mds.26431
Abstract
MDS clinical diagnostic criteria for Parkinson’s disease
This document presents the Movement Disorder Society Clinical Diagnostic Criteria for Parkinson’s disease (PD). The Movement Disorder Society PD Criteria are intended for use in clinical research but also may be used to guide clinical diagnosis. The benchmark for these criteria is expert clinical diagnosis; the criteria aim to systematize the diagnostic process, to make it reproducible across centers and applicable by clinicians with less expertise in PD diagnosis. Although motor abnormalities remain central, increasing recognition has been given to nonmotor manifestations; these are incorporated into both the current criteria and particularly into separate criteria for prodromal PD. Similar to previous criteria, the Movement Disorder Society PD Criteria retain motor parkinsonism as the core feature of the disease, defined as bradykinesia plus rest tremor or rigidity. Explicit instructions for defining these cardinal features are included. After documentation of parkinsonism, determination of PD as the cause of parkinsonism relies on three categories of diagnostic features: absolute exclusion criteria (which rule out PD), red flags (which must be counterbalanced by additional supportive criteria to allow diagnosis of PD), and supportive criteria (positive features that increase confidence of the PD diagnosis). Two levels of certainty are delineated: clinically established PD (maximizing specificity at the expense of reduced sensitivity) and probable PD (which balances sensitivity and specificity). The Movement Disorder Society criteria retain elements proven valuable in previous criteria and omit aspects that are no longer justified, thereby encapsulating diagnosis according to current knowledge. As understanding of PD expands, the Movement Disorder Society criteria will need continuous revision to accommodate these advances.
“MDS clinical diagnostic criteria for Parkinson’s disease” by Ronald B. Postuma MD, MSc, Daniela Berg MD, Matthew Stern MD, Werner Poewe MD, C. Warren Olanow MD, FRCPC, Wolfgang Oertel MD, José Obeso MD, PhD, Kenneth Marek MD, Irene Litvan MD, Anthony E. Lang OC, MD, FRCPC, Glenda Halliday PhD, Christopher G. Goetz MD, Thomas Gasser MD, Bruno Dubois MD, PhD, Piu Chan MD, PhD, Bastiaan R. Bloem MD, PhD, Charles H. Adler MD, PhD and Günther Deuschl MD in Movement Disorders. Published online October 16 2015 doi:10.1002/mds.26424
Abstract
MDS research criteria for prodromal Parkinson’s disease
This article describes research criteria and probability methodology for the diagnosis of prodromal PD. Prodromal disease refers to the stage wherein early symptoms or signs of PD neurodegeneration are present, but classic clinical diagnosis based on fully evolved motor parkinsonism is not yet possible. Given the lack of clear neuroprotective/disease-modifying therapy for prodromal PD, these criteria were developed for research purposes only. The criteria are based upon the likelihood of prodromal disease being present with probable prodromal PD defined as ≥80% certainty. Certainty estimates rely upon calculation of an individual’s risk of having prodromal PD, using a Bayesian naïve classifier. In this methodology, a previous probability of prodromal disease is delineated based upon age. Then, the probability of prodromal PD is calculated by adding diagnostic information, expressed as likelihood ratios. This diagnostic information combines estimates of background risk (from environmental risk factors and genetic findings) and results of diagnostic marker testing. In order to be included, diagnostic markers had to have prospective evidence documenting ability to predict clinical PD. They include motor and nonmotor clinical symptoms, clinical signs, and ancillary diagnostic tests. These criteria represent a first step in the formal delineation of early stages of PD and will require constant updating as more information becomes available.
“MDS research criteria for prodromal Parkinson’s disease” by Daniela Berg MD, Ronald B. Postuma MD, MSc, Charles H. Adler MD, PhD, Bastiaan R. Bloem MD, PhD, Piu Chan MD, PhD, Bruno Dubois MD, PhD, Thomas Gasser MD, Christopher G. Goetz MD, Glenda Halliday PhD, Lawrence Joseph PhD, Anthony E. Lang OC, MD, FRCPC, Inga Liepelt-Scarfone PhD, Irene Litvan MD, Kenneth Marek MD, José Obeso MD, PhD, Wolfgang Oertel MD, C. Warren Olanow MD, FRCPC, Werner Poewe MD, Matthew Stern MD and Günther Deuschl MD in Movement Disorders. Published online October 16 2015 doi:10.1002/mds.26431
