Dementia: The Parkinson’s Prophecy

26. September 2017
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A characteristic aspect of Parkinson's disease is the presence of movement disorders. However intellectual abilities are also often impaired by the degradation processes in the brain. Neurologists have now developed a risk score to predict the course of progress of cognitive functions.

Most often, Parkinson’s disease begins at between 50 and 79 years of age. The main symptoms are disorders affecting the ability to move: ranging from increasing muscle stiffness (rigor), slowed movements (bradykinesia) and a lack of movement (akinesia) to muscle tingling (tremor) and a disorder affecting upright body posture (postural instability). However, other symptoms frequently occur in the course of the process – these may include psychological symptoms such as increased depression, disorders of the sensory system, for instance a reduction in the sense of smell (hyposmia), and vegetative symptoms such as disorders of bladder and gastrointestinal functions.

Many patients with Parkinson’s disease also suffer increasingly from cognitive impairments. Hence 24 to 31 percent of sufferers over time develop dementia. Even in the early stages, cognitive impairments can often be observed: the incidence of mild cognitive impairment in newly diagnosed patients who had not yet received any medication amounted to 14.8 percent – in a comparable sample of healthy people this figure was only 7 percent. The likelihood of cognitive impairment increases significantly as the age, severity and duration of the disease increases.

In contrast to Alzheimer’s disease, with Parkinson’s syndrome the disturbance of memory is not prominent. Instead, a range of different cognitive abilities can be affected: attention, learning and retrieval of information, visual-spatial perception, linguistic abilities and so-called executive functions, such as setting goals and planning actions. In addition, a general cognitive slowdown is often observed. For example, it is increasingly difficult for the affected person to work with several stimuli at the same time or to plan their daily lives. They process stimuli more slowly, perform tasks more slowly and their language becomes increasingly impoverished.

7 factors that predict cognitive impairment

Now a researcher team led by Clemens R. Scherzer from the Harvard Medical School and the Brigham and Women’s Hospital in Boston (USA) in doing a longitudinal study has developed a measuring instrument designed to predict the future cognitive impairment or the development of dementia in patients with Parkinson’s disease.

The study included nine study groups taking in Parkinson’s patients from North America and Europe, in relation to whom data was repeatedly collected between 1986 and 2016. Six cohorts with a total of 1,350 patients were used to develop the predictive instrument, three cohorts with a total of 1,132 patients were used for checking and replicating the results. At the time of the diagnosis, none of the patients showed cognitive impairments.

Based on the results of previous studies, the researchers used the following data to derive the predictive measure: age at onset of disease, gender, presence of depression and the duration of education (in years). Furthermore, the initial result obtained for the Mini Mental Status Test (MMST), the results of three motor tests for Parkinson’s patients (the Unified Parkinson’s Disease Rating Scale II and III as well as the Hoehn & Yahr Scale for motor symptoms) and mutations of the gene for β-glucocerebrosidase (GBA) were factored in. Such mutations are associated with an increased risk of Parkinson’s disease.

Two measures – the results of the Unified Parkinson’s Disease Rating Scale II and the Hoehn & Yahr Scale for Motor Symptoms – had no additional predictive value and were therefore not considered further. The remaining seven factors were assessed with different weighting in the calculation of a cognitive risk-score, which ends up being between 0 and 1.

Predictability accuracy of 85 percent

The thus developed risk level predicted the cognitive impairments in the first ten years after diagnosis with an accuracy of 85 percent – and the development of dementia during this period with an accuracy of 88 percent. “Using our risk-scores the predictive capacity of future cognitive performance of patients with Parkinson’s disease could be improved”, Scherzer explains. “Measures to improve or stabilise cognitive abilities, such as through medication or cognitive training, could be developed and tested more specifically if only high-risk patients are included in the studies”. This would allow the sample size to be reduced and the chances of successful treatment approaches to significantly increase.

Is the risk score helpful in the clinic?

How does Günter Höglinger, head of the Clinic for Parkinson’s Syndrome at the medical centre Rechts der Isar, at the Technical University München (Germany), assess the risk score: “The aspects that contribute to the predictive measure are known risk factors for dementia”, he says. “Until now, I have not been aware of any such risk score”. In his view, the newly developed risk score will not likely establish itself as clinical routine work, but it could be useful for research purposes.

Even though GBA mutations were not included in the evaluation, predictive accuracy was still very high, Scherzer and his team report. Thus, the calculation of the risk-score is possible using clinical data alone, without complicated genetic investigations, they write.

One way to calculate the risk-score has already been made available by the researchers on-line for other scientists. In order for the predictive-algorithm to be employed in clinical practice, however, it still has to be tested out in further prospective studies, Scherzer and his team emphasise.

How are motion disorders and cognitive performance related?

The explanation as to why Parkinson’s disease is associated with cognitive disorders in addition to motor symptoms lies in the nerve cells of the brain. Various investigations have shown that Parkinson’s disease leads to the death of nerve cells in deeper regions of the brain – especially in the brain’s basal ganglia, which play an important role in the control of movements. The destruction of the nerve cells leads to a deficiency of the messenger chemical dopamine, whereby motor activation is disrupted. At the same time changes occur to other messengers in the brain: in particular to acetylcholine, but also to serotonin and noradrenaline.

Several studies have now dealt with whether there is a link between certain disorders affecting the ability to move and certain cognitive impairments. A connection between slowed motor ability and slight cognitive impairments or inflexible thinking was observed, whereas cognitive impairments rarely appeared in patients with a tremor.

In one current study a research team led by Jian Wang from Huashan Hospital in China studied 96 Chinese Parkinsons patients, as to how certain motor symptoms are related to different aspects of cognitive performance. The scientists established that disorders of attention and executive functions (ie. the ability to plan and control) are associated with slow movements and muscle stiffness whereas disturbances of visual-spatial abilities are associated with tremor, but also with slowed movements.

Understanding neural networks behind the symptoms

The results could indicate that there are different types of Parkinson’s disease, which affect different networks in the brain. Thus, slowed movements and inflexible thinking could relate to disorders of a particular dopaminergic network in the brain, whereas with tremor another network could be playing a role.

Studies already show that dopamine deficiency in the basal ganglia and in networks that connect the basal ganglia to the frontal brain also plays a role in impairment of executive functions. The research group led by Wang was also able to demonstrate that the cognitive abnormalities of Parkinson’s patients are associated with decreased activity in the forehead and temporal lobes of the brain.

“Future studies should examine the relationship between motor and cognitive functions over a longer period”, Wang and his team emphasise. “Such results could help better predict the course of Parkinson’s disease. In addition, they could facilitate the development of new treatment options for relieving symptoms”.

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Image copyright: Rajeev Rajagopalan, flickr / Licence: CC BY-SA

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1 comment:

Christian KOK
Christian KOK

Parkinson as well as Alzheimer and ALS, Autism are surely man made diseases!
The whole bigpharma(ffia) is profiting these disorders .
The elite are creating like so many lots of money out of this. If you know that Aluminum is highly responsable for brain degeneration, and Barium affecting the heart, you`ll notice what all about they are spraying day in and out .
Our govt is only telling you it are contrails 9condensation trails) but that`s not the truth !
More unsalted news you`ll hear on or google for Dane Wigington , Kristen Meghan, Willem Felderhof former KLM pilot, or Ir. Coen Vermeeren. Take a look at youtube: `What In The World Are They Spraying?`And share your knowledge on FB group: Chemtrails Global SkyWatch or Chemtrails Benelux . Thx for resetting your mind and true awakening.

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