Currently,general knowledge states that a patient who has a persistent disorder ofconsciousness for more than twelve months is unlikely to recover. This createsa very hard decision for family members of patient’s in a vegetative state whomust decide how take care of these patients who are alive yet unresponsive. Inthe article by Neuroscience Newscalled “After 15 Yearsin a Vegetative State, Nerve Stimulation Restores Consciousness” new hope iscreated for possible treatments for patients who have been in a persistentlyvegetative state. The study examined inthis article is a case study of a 35 year old man who had been in a vegetativestate for 15 years following a car accident. He had shown no evidence ofimprovement and therefore was chosen for the stimulation study because anyimprovement could be more easily linked to the treatment.
The patient had avagus nerve stimulator implanted in his chest and the stimulator was run for amonth. After a month, neuropsychological tests, an EEG and PET scan were run.The neuropsychological tests showed an improvement in orientation as thepatient was now able to follow an object with his eyes, turn his head uponrequest and stay awake when his therapist was reading to him. The EEG showed anincrease in overall brain activity, and the PET scan for metabolic activityshowed an increase in functional connectivity throughout both cortical andsubcortical regions. These changes indicated that the patient had entered aminimally conscious state after 15 years in a vegetative state.
This research is veryimportant as it upturns the idea that a patient will not recover from avegetative state after more than a year of persistent disturbances inconsciousness. It also introduces new treatment possibilities or at least newareas of research for treatment. In addition, the return of consciousnesssuggests that the brain may be more plastic and have a larger capacity forrepair than previously believed, and suggests that certain interventions canassist in speeding this healing even after long term damage. Finally, thisstudy gives more evidence for how consciousness occurs. By seeing thatconsciousness can be recovered after such a long disturbance and with electricalstimulation may suggest that consciousness is tightly linked to the electricalactivity in the brain and that the level of electrical activity may be whatcreates consciousness. This seems like a reasonable explanation as EEG studiesare currently used to understand different levels of consciousness.
The main limitation ofthis study is the fact that it is a case study and thus is not generalizable.Although it does provide interesting information that can be used to developfurther research studies, it only provides anecdotal evidence of theeffectiveness of the treatment. In addition, since the disturbance is impliedto be due to a traumatic injury the treatment may not be effective for loss ofconsciousness in disturbances caused by infections or neurodegenerativedisorders. Limitations of the media article include the lack of detail on wherethe brain damage occurred or where exactly improvement on the PET scan wasseen. This is a problem, as the results may not be generalizable to braindamage in other regions.
Also, it is important to understand which areas of thebrain showed improvement on the PET scan in order to hypothesize which parts ofthe brain may be the most linked to consciousness. The article did not detailwhy stimulation to the vagus nerve instead of another area was decided on. Thiswould be important information for understanding how why vagus nervestimulation resulted in the re-development of consciousness. Finally, thearticle does not mention the reaction of other medical professionals and if theyapproved of the studies protocols and conclusions. This is an issue because ofthe lack of even informal peer review. Astrength of the article is that it was very objective and stuck to the factswithout providing further conclusions or interpretation.
The main relation thisarticle had to class concepts was in the neuroimaging chapter. The study shows whyPET scans can be more advantageous than fMRIs in some cases. In class, we discussedhow PET scans had low temporal resolution and how activated areas seen on thescan may not be essential to the task. For these reasons, we said that fMRI wasusually favored over PET but that PET could be very useful in the medicalfield.
This use in the medical field was shown through this study in how theinterest was more in gross connectivity rather than task specific activity. ThePET scan was favored here because exact functioning was not desired so lowtemporal resolution with PET was not considered a disadvantage and the cheapernature of PET made PET the better choice. In addition, this study shows wheninvasive electrode stimulation is appropriate in humans.
Although, as discussedin class, electrode stimulation is primarily used in animals, this shows how itcan be used in humans in extreme cases. Although the location of brain damagewas not explicitly stated in this article, the research shows the importance ofthe brain stem in consciousness. In class, the brain stem was discussed as aplace where if brain damage occurred life was majorly in danger. This studyshows this in the lack of consciousness.