May 30, 2016
Early diagnosis and starting treatment as early as possible are decisive factors in achieving improved quality of life for Parkinson's sufferers. Experts are discussing a wide range of new insights into the early stages of the disease at the Congress of the European Academy of Neurology in Copenhagen.
"New, neuroprotective or disease-modifying
therapies against Parkinson's could be far more effective if administered at an
early stage of the disease. Fortunately, we are increasingly able to decipher
the mechanisms by which the condition develops thanks to the latest findings
and methods, which enables us to identify persons at risk of developing
Parkinson's early on," commented Prof Günther Deuschl of the University
Medical Center Schleswig-Holstein in Kiel, and President of the European
Academy of Neurology (EAN), at the second EAN Congress in Copenhagen. New insights
into the early stages of Parkinson's are among the main topics under discussion
at this major medical event.
EAN President Günther Deuschl underlined the
growing importance of early recognition, particularly in light of current
demographic trends: "Parkinson's disease affects around 2 percent of
over-65s and is one of the most common neurodegenerative conditions in Europe,
with about 1.2 million cases across the continent. In view of increasing life
expectancy, the number of sufferers is expected to double by 2030."
Parkinson's is also highly significant in terms of disability-adjusted life
years (DALYs), a measure of the number of years of life lost to illness and
premature death. "In the EU, some 640,000 healthy years of life are being
lost to this disease. Today, Parkinson's is ranked fifth in the list of the
most expensive neurological conditions facing Europe's health systems. That
makes it all the more important to devise innovative approaches that prevent
the progression of the disease as effectively as possible," Prof Deuschl
explained.
Keeping an eye open for risk markers – from
impaired sense of smell to muscle weakness
The pathology of Parkinson's disease begins
long before clinical diagnosis. More and more studies have shown that many
symptoms appear several years prior to the identifiable degeneration of nerve
cells and the onset of typical motor impairment. These include hyposmia,
constipation, dizziness and urinary dysfunction. A special type of sleep
disorder, known as REM-sleep behaviour disorder, is another such symptom. In
healthy individuals, motor functions are inhibited during this phase of sleep,
but sufferers of this condition actually physically enact their dreams.
"A long line of studies being presented at
the EAN Congress confirm the existence of risk markers that are not necessarily
associated with Parkinson's disease at first glance, and as such are easily
missed," said Prof Deuschl. One of these studies, an analysis of 40
Parkinson's patients compiled by French researchers, shows that the respiratory
function of those with the disease is significantly weaker than that of healthy
individuals. It appears that in the early stages of the disease, the function
of the muscles involved in breathing is impaired.
An Italian study also presented at the EAN
Congress looked at the olfactory performance of Parkinson's patients at an
early, undiagnosed stage of the disease, and compared this with the sense of
smell of a control group consisting of healthy people of the same age. The
control group's stronger sense of smell may be the result of a better cortical
connection to the caudate nucleus, a part of the basal ganglia that is involved
in controlling voluntary movements. Researchers from Russia, who studied 104
patients, illustrated the prevalence of olfactory
dysfunction among Parkinson's sufferers. Eight out of ten
participants in the study had hyposmia, while almost one in five were anosmic
and only two subjects had no impairment.
Biomarkers and intestinal biopsies as tools for
early recognition
Risk markers are only one of the areas where
researchers have gained new insights. It appears that alpha-synuclein, a
protein, plays a decisive part in the progression of the disease.
"Alpha-synuclein agglutination in the brain is a significant factor. It
seems that this pattern of damage is passed on from cell to cell – so future
therapies should be aimed at stopping or at least delaying this chain
reaction," Prof Deuschl pointed out. There is increasing evidence that
pathological changes occur not only in the brain, but also in other nerve
cells, for instance in the intestines, and that they possibly
"migrate" from there to the brain. Typical protein damage has also
been found in skin cells and the salivary glands. "These findings are
opening the door to new approaches for the early recognition and treatment of
Parkinson's disease. Detailed research is under way to establish whether a
biopsy of the nerves in the intestines, salivary glands or skin permits a
conclusive early diagnosis of the condition," said Prof Deuschl.
More reliable estimate of the probability of
developing Parkinson's
The definition of criteria for diagnosing
Parkinson's in the prodromal phase of the condition – in other words, a very early stage when
conventional clinical diagnosis based on motor symptoms is not possible – is a
major step forward in terms of early recognition of the disease. "The
criteria were recently published by the Movement Disorder Society. They are
designed to standardise clinical research and provide diagnostic support,"
Prof Deuschl explained. "There are still no reliable tests for early
diagnosis of Parkinson's, so doctors have had to rely on experience alone. But
now we have developed a completely novel neurological approach that links
clinical examinations and statistical calculations of probability." The
starting point is the likelihood that an individual will develop the condition,
based on their age. As much diagnostic information as possible is then
collected and evaluated using a likelihood ratio. The information can include environmental
risks such as smoking or caffeine consumption, genetic factors, the results of
biomarker tests and prodromal symptoms such as constipation or olfactory
dysfunction. This means that risk factors can be considered as either positive
or negative influences. "The risk assessment system can be extended as
required when new tests to support early diagnosis are
developed," according to Prof Deuschl.
More information:
G. Baille et al: Ventilatory disturbance in early Parkinson's disease: a
prospective study; EAN 2016 Abstract
S. Marino et al: Resting state functional
connectivity in olfactory network in de novo Parkinson's disease; EAN 2016
Abstract
M. Titova et al: Objective olfactory testing
and self-assessment of olfactory function in patients with Parkinson's disease
R.B. Postuma et al: The new definition and
diagnostic criteria of Parkinson's disease, in The Lancet Volume 15, No.
6, p546-548, May 2016
Journal reference: The Lancet 
Provided by: European Academy
of Neurology
https://www.sciencedaily.com/releases/2016/05/160530101300.htm?
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