A human brain, with the cerebellum colored in purple
Drawing of the human brain, showing cerebellum and pons
|SCA, AICA, PICA|
|Anatomical terms of neuroanatomy|
Dyschronometria is the medical term used to describe a patient who cannot accurately estimate the amount of time that has passed (i.e., distorted time perception). This can be a sign of cerebellar ataxia. which is when the cerebellum has been damaged and does not function to its fullest ability. Lesions to the cerebellum can cause dyssynergia, dysmetria, dysdiadochokinesia, dysarthria, and ataxia of stance and gait. as well as a precursor for a patient who will be having a stroke. Dyschronometria is an autosomal dominant cerebellar ataxia (ADCA) which usually means the ataxia is a less debilitating than an autosomal recessive cerebellar ataxia, or an ataxia that is linked to the X-chromosome.
Signs and symptoms
Common signs of having dyschronometria are lack of spatial awareness, poor short term memory, inability to keep track of time. These signs and symptoms are only the most generic and are not explicitly isolated to having dyschronometria, because these are also signs of having any type of Cerebellar ataxia.
In patients with dyschronometria, keeping track of small amounts of passage of time also proves to be difficult. When asked to wait for thirty seconds, or tap every second that has gone by, those affected will be able to perform the task for a short time and then become quickly derailed by the task. Usually this is because they lose focus however more often than not, the individual affected can no longer tell what they are doing, seeming to become lost. This symptom, while not completely understood, is one of the more obvious to notice for those with this cerebellar ataxia. This often takes form in forgetting basic time keeping unless a timer is set, such as when cooking for example. The inability to keep track of time applies only to the keeping track of seconds, minutes and at the most hours. It does not apply however to the macro level having to do with circadian rhythm because they are able to function biological as they had before.
The greatest common cause of cerebellar ataxias, especially that of dyschronometria, all involve the cerebellum taking damage. This can be by form of a trauma or by natural causes of disease and genetics. Examples of trauma include a car accident, stroke, epilepsy, and head trauma. These traumas are especially detrimental to elderly and children due to the decrease in brain matter, thus making these events if taken place have an increased risk of damaging the cerebellum. This also explains why we see dyschronometria more common in elderly due to the deterioration of physical brain matter. Other probable causes for the deterioration of brain matter in the elderly include increased supranational activation, decreased cerebellar activation (which is consistent with fronto-cerebellar dissociation).
As mentioned before several genetic causes exist. These include chicken pox as well as any version of chicken pox that can infect the nervous system, brain tumors, toxic reactions to released toxins in the blood stream, transient ischemic attacks, cerebral palsy, multiple sclerosis, degenerative disorders, and genetics. Unlike trauma, it is harder to catch the dyschronometria within those diagnosed with it because it hides beneath these other diseases.
An interesting case of dyschronometria has to do with dyslexia. While not completely studied, when dyslexia was studied within children, they found that these children were often stressed as well as mentally exhausted. This had to do mostly with their inability to understand time and allocate it correctly as well as understanding basic words due to their dyslexia leading on almost a snowball effect to where they had symptoms of dyschronometria. These children would place little to no importance on their present state, which was a habit that continued into adulthood. This brings about the question of whether dyslexia is a symptom or a cause of dyschronometria, or both. When looking into dyslexia in adults, the question was still unanswered, and further research will need to be done in order to completely understand just how dyslexia, in the context of this cerebellar ataxia, is to be classified.
Lastly, dementia has a huge effect on dyschronometria and was one of the main sources of how dyschronometria was discovered. Through studies, dementia is both a cause and an effect of dyschronometria. This has to do completely with the fact that with Dementia the brain is constantly rewiring itself and thus information becomes lost causing the person who had dementia to become confused as well as disoriented, and in most causes completely unaware of the passage of time. As a cause, dyschronometria causes the person to because disoriented and completely unaware of time, thus making bits and piece of their brain involving a memory to become lost ultimately leading to dementia in the long term. This is how dyschronometria is a precursor to dementia.
Errors and Inaccuracies
Difficulty in recognizing dyschronometria's easily recognizable symptoms is that it also tends to show up with other Cerebellar Ataxias that effect Gait, speech and thought process. These other ataxias also use the same symptoms of lacking spacial recognition and time disorientation to diagnose those ataxias as well covering up the fact most these patients also have dyschronometria. The most common ataxias dyschronometria has been seem to be evident with are dyssynergia, dysmetria, dysdiadochokinesia, dysarthria as well as the ataxias effecting stance and gait. Dyslexia is also another problem with those individuals affected by Dyschronometria, however it is unsure weather Dyslexia is developed or worsened by having Dyschronometria, or if it is the exact opposite where having the dyslexia increases the chance to develop dyschronometria. Another problem that dyschronometria faces in detection is that Dyschronometria is a relatively new name for this side effect and precursor to dementia compared to other cerebellar ataxias such as the ataxias mentioned above. When dyschronometria is detected on the other hand, it is usually found when the symptom has progressed to the point where it can not be reversed or provide any type of benefit for taking the testing medication to either slow down dyschronometria or the process of dementia setting in which is what dyschronometria is a signal for.
However the greatest error in diagnosing dyschronometria is that this cerebellar ataxia hides itself with the symptoms and signs it shows. The signs that those who are diagnosed with dyschronometria are not obvious, and oftentimes are mistaken to be other cerebellar ataxias or dementia by medical professionals. In addiction these medical professionals usually expect to see signs of the circadian rhythm being disrupted by either their sleeping cycles and patterns have no logical sense to it, which have nothing to do with dyschronometria. Other error in diagnosing dyschronometria included the idea that those who have dyschronometria have a speech impediment or suffer from delusions border lining psychosis, impairment of long term memory, as well as the complete loss of conscious understanding of time. These misconceptions mentioned mostly stem from the fact that this cerebellar ataxia is rarely diagnosed without being seen in dementia or with another ataxia.
Testing and diagnosing for dyschronometria also has shown not to be effective as well. The reason why dementia is caught so late when the signals seem as obvious as mentioned above is due to the fact that psychological tests that have been done to try to catch signs of dementia, such as dyschronometria, are not very helpful. This is due to the bell curves that are formed after the statistical analysis, and due to the normal subjects having a wide range, the only patient that is caught by these tests are the subjects that have such an abnormal showing it is obvious even without tests that there is a problem. If there was a way to create a more sensitive testing, perhaps scientists would be able to catch Dementia quicker. Diagnosing of dyschronometria is also difficult due to the lack of research as well as professionals concentrating in this cerebellar ataxia. Neuroscientists are only just starting to do more research into this lack of awareness and keeping time. When the science and the tests are more specialized and this topic has been looked into at a greater depth, the sensitivity of the tests that have been and will be conducted will be able to give more answer to the questions that are continuing to arise.
The cerebellum has not been tested clinically with whether or not there is a significance influence by drugs to help the repairmen of various cerebellar ataxias. In the research done by Trouillas in Lyon France, it was considered to be logical to examine the pharmacology of cerebellar ataxia by manipulating the key components found at the nerve level within the cerebellum or the inferior Olive. This was done mostly through the modification of the GABA, dopamine, and serotonin receptors which did seem to show positive results in the primary stages of the experimentation. The clinical benefits presented in this study justifying the prescription of d-l-5-HTP or better with the l-5-HTP with benserazide to patients with certain cerebellar ataxias including that of Dyschronometria. At the present as stated, this is the best indication for treatment of the cerebellar cortical atrophies. Even still it is important to stress that the response to this treatment may be slow and irregular.
Previously, neuroplasticity used as a rehabilitation method were looked into as a potential treatment for dyschronometria. However these studies were not further developed since the 1980s. With current techniques and research from the neuroscience community, this is still a viable option not to eliminate the cerebellar ataxia, but to slow its progress of development.
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- National Ataxia Association
- Dementia: Signs, Symptoms, and Diagnosis
- Journal of Neuroscience
- Society of Neuroscience
- National Ataxia Foundation