Posts Tagged ‘locked-in syndrome’

Walking But Unconscious; Unmoving but Conscious

September 9, 2018

This post is taken from Michael Gazzaniga’s outstanding book, “The Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind.” Strange behaviors can also arise from a fully intact and functioning brain if only part of it is awake. In a layered brain, lots of activities are happening simultaneously and coordinated synchronously. Here is what can happen when things get out of sync.

Mr. A was described by family and friends as a loving family man. He was awakened in his bed by his dogs’ barking and strange voices. Racing downstairs, he was met by several police officers with their guns drawn. Dazed and confused, he was cuffed and locked in the back of a squad car trembling in fear as he tried to assess the situation by listening to the conversation of emergency personnel through the window. He gathered that his wife had been badly hurt and thought that the cops were on the hunt for the person responsible. He didn’t know until later that they had already found their man, and it was he.

The police summarized the incident. Mr. A brutally murdered his wife during what was later determined to be a sleepwalking episode. During this episode, he had gotten up from bed and gone out to fix the pool’s filter, which his wife had asked him to do at dinner. She most have awoken and gone down to coax him back to bed. His concentration on the motor interrupted, he had turned violent and stabbed her 45 times, put his tools away in the garage, returned to find her still alive, and rolled her into the pool where she drowned. He then returned to bed. His neighbor hearing screaming and barking, looked over the fence to see a “bewildered”- appearing Mr. A roll the body into the pool. The neighbor then called the police.

He was tried and found innocent. The jury found that since no identifiable motive, no attempt to hide the body or weapon, and no memory of the event, the jury was convinced that his actions occurred unintentionally and out of Mr. A’s awareness. So, what went on in Mr. A’s mind and brain during this atrocity?

Sleepwalking is a parasomnia, strange behavior that occurs during sleep. Sleep experts have identified two main stages of sleep by recording brain waves—rapid eye movement (REM) and non-rapid eye movement (non-REM) sleep. Sleeping walking usually occurs after abrupt and incomplete spontaneous arousal from non-REM sleep that occurs during the first couple of hours of the night, turning one into a mobile sleeper. Trying to waken sleepwalkers is fruitless and can be dangerous, since the sleepwalker may feel threatened by physical contact and respond violently.

Neuroimaging and EEG has provided a clearer picture of what is happening in the brain during non-REM sleep. The brain appears to be half awake and half asleep: the cerebellum and brainstem are active, while the cerebrum and cerebral cortex have minimal activity. The pathways involved with the control of complex motor behavior and emotion generation are buzzing, while those pathways projecting to the frontal lobe, involved in planning, attention, judgment, emotional face recognition, and emotional regulation are zoned out. Sleepwalkers don’t remember their escapades, nor can they be awakened by noise or shouts, because the parts of the cortex that contribute to sensory processing and formation of new memories are snoozing, temporarily turned off, disconnected, and not contributing any input to the flow of consciousness.

One of the worst brain injuries is a lesion to the ventral part of the pons in the brainstem. The loss of these neurons, which connect the cerebellum with the cortex, leave one unable to move but fully conscious. This happened to Jean-Dominique Bauby, the editor in chief of the French “Elle” magazine when he suffered a stroke at the age of 43. Waking up several weeks later from a coma, fully conscious and with no cognitive loss, he was unable to move anything except his left eyelid. He could not talk so he could not tell anyone he was conscious. He had to wait until someone noticed that he appeared to voluntarily move his eyelid. This is called the “locked-in” syndrome. The so-called lucky ones who voluntarily blink or move their eyes, though the movement is small and tiring. This is how they communicate. The unlucky ones cannot.

Bauby was able to blink and he took advantage of his ability to blink his eye to write a book. He described his conscious experience as he lay paralyzed. He would construct and memorize sentences as he lay there. Then for four hours a day, a secretary patiently sat at his bedside going through a frequency-ordered French alphabet so he could blink when the correct letter was spoken. Two hundred thousand blinks later “The Diving Bell and the Butterfly” was done. A movie was made based on the book. Both the book and the movie are highly recommended.

Bauby is an example of the endless capacity of human adaptability. Adaptability appears to be the norm for such patients. 75% have rarely or never had suicidal thoughts. Gazziniga writes, “Even with this devastating injury to part of the brainstem, consciousness remains, accompanied b the full range of feelings about both present and past experiences.

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The Silent

May 14, 2016

The fifth cryptomind discussed in “The Mind Club” is The Silent.  This chapter is about those we cannot communicate with who, because of trauma to the brain, cannot communicate with us.  The EEG can be used to take measurements.  Disordered conscious states can be diagnosed by the EEG patterns.  An ordering of conscious states follows:

Wakefulness
Locked in syndrome
Minimally conscious
Coma
Vegetative State
Brain Death

It is unfortunate that unless EEG measurements are done along with further diagnosis the Locked in syndrome can be mistaken for a lower level of consciousness.

The term locked-in syndrome was coined by Fred Plume and Jerome Posner.  For many years it was not realized that someone was actually locked-in.  Healthy memory remembers watching a movie when someone asked suppose some is locked inside the unconscious state.  The reply was that that was something too horrible to imagine.  But there are real people who can accomplish some impressive feats.  Jean-Dominique Bauby was an editor who suffered a stroke and found himself locked-in.  But he was able to communicate by blinking his one eye that was functioning.  It took him 200,000 blinks to write the Diving Bell and the Butterfly.  He lived to see the book published, but he died before he saw the enormous success of the book and the beautiful movie  with the same title that was based on the book.

People react and adapt to this locked-in state differently.  Bauby could have continued a productive career had he not died.  But an Englishman, Tony Nicklinson, did not and wanted to commit suicide.  However, being locked-in he could not commit suicide.  He petitioned the court to allow doctors to provide an assisted suicide.  After much deliberation, the courts decline.  However, he did manage to commit suicide by refusing to swallow.

In addition to EEGs, fMRIs can provide very useful information.  The primary problem with fMRI’s is that they are expensive.

To read more about current research on this topic, see some of the healthy memory blog posts by Dehaene (see the Healthymemory blog post titled, “The Ultimate Test”).

The authors of  “The Mind Club” also examine the other end of life.  That is, when does life begin.  This is a large religious issue that can impact people of different religious beliefs.  A symposium organized in 1968 by the Christian Medical Society affirmed that “the preservation of fetal life…may have to be abandoned to maintain full and secure family life, as well as in cases of rape, incest, fetal deformity, and threat to the mother’s well-being, whether physical or emotional.  However, evangelical opinion swung after church leaders such as the eminent Jerry Falwell reacted to the 1973 Roe v. Wade decision and advocate a “life at conception” interpretation of the Bible.   As the Catholic Church claims that life begins at conception certain Protestant sects did not want to appear remiss.

However, if memory serves healthy memory correctly, at one time there were arguments among Catholic philosophers as to when the soul entered the body.  Furthermore, healthy memory believes that there were different times depending upon whether a male of female was involved.  If any readers can help me out on this particular point, it would be much appreciated.

Nevertheless, it is healthymemory’s belief that the soul is the issue.  The soul is a religious entity and the argument should be argued in theological terms.  Biological terms are irrelevant.

© Douglas Griffith and healthymemory.wordpress.com, 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

The Ultimate Test

April 7, 2016

The Ultimate Test is the sixth chapter of “Consciousness and the Brain:  Deciphering How the Brain Codes our Thoughts” is an outstanding book by the French neuroscientist Stanislas Dehaene who is the Chair of Experimental Psychology at the College of France.  This is the seventh consecutive post on this outstanding book. According to Dr. Dehaene the ultimate test of any theory of consciousness is the clinic.  Every year thousands of patients fall into a coma.  Unfortunately, many of these patients will remain permanently unresponsive in a dreaded condition called the “vegetative state.”  Worse yet, is that in Intensive Care Units (ICUs) over all the world, half of the deaths result from a clinical decision to remove life support.  How many of these decisions are wrongly made?

Coma is defined  clinically as a prolonged  loss of the capacity to be aroused.  However, coma patients are not brain-dead.  Brain death is a distinct state,characterized by a total absence of brain stem reflexes.  In brain-dead patients, positron emission tomography (PET) and other measures such as Doppler ultrasonography show that cortical metabolism and the perfusion of blood to the brain are annihilated.  Most countries, the Vatican included, identity brain death with death, period.

What is of primary interest is the “locked-in syndrome.”  This state typically results from a well-delimited lesion, usually on the protuberance of the brain stem.  Such a lesion disconnects the cortex the cortex from its output pathways  in the spinal cord.  If the cortex and the thalamus are spared, it often leaves consciousness intact.  As you can well imagine, this is a terrible state in which to find oneself.

The book “The Diving Bell and the Butterfly” (there is also an outstanding movie by the same name) was written by Jean-Dominique Baby, who was the editor of the French fashion magazine, “Elle.”  He wrote this book one character at a time by blinking his left eyelid while an assistant recited the letters of the alphabet.  He eloquently told his story with two hundred thousand blinks telling the story of a beautiful mind shattered by a cerebral stroke.  Fortunately he lived to se the book published, but, unfortunately, he died three days later.

Comparatively speaking, Jean-Domonique Baby was well-off. Many locked-in patients have no motor responses, no means of communicating with the world.  Fortunately fMRIs can identify these individuals, given enough time.  Unfortunately, fMRIs are extremely expensive and are beyond the budgets of too many medical facilities.  But, fortunately, Dr. Dehaene has developed an inexpensive test using EEG recordings using 256 electrodes.  Information exchanged over long cortical distances is an excellent index of consciousness in patients with brain lesions.  Computations are done for each pair of electrodes for a mathematical index of the amount of information shared by the underlying brain areas.  Vegetative-state patients showed a much smaller  amount of shared information than conscious patients and control patients.  This finding fits with  with a central tenet of global workspace theory, that information exchange is an essential function of consciousness.  A follow-up study showed that the few vegetative patients who showed high information sharing had a better chance of regaining consciousness within the next days or  months.

So technology and the global workspace theory provide good diagnostic techniques.  It is hoped that interventions will be developed in the future to unlock those in a locked-in state.  Dr. Dehaene has described some promising work being done in this area.