Myers’ Shell Shock Patients Had Loss of Smell
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Previous pages in this series have focused on the contrast between the quality of the meticulous description of history by Charles Myers’ in his seminal 1915 Lancet paper on “Shell Shock” and his clearly flawed comment that these case studies were explained by hysteria. See “A Contribution to the Study of Shell Shock” published in the British Medical Journal, the Lancet, on February 13, 1915.
Our previous part focused on how he documented, but didn’t find significant evidence of amnesia. This part will focus on the loss of smell and taste as clear historical markers than Myers’ patients had brain injury.
Loss of Smell Correlates to Brain Injury in Combat
As thoroughly as we have criticized Myers’ conclusions, we must applaud the thoroughness of his investigative skills. One of the great flaws of current neurological exams is the failure to test all cranial nerves. The words “Cranial Nerves II through XII are intact” are tantamount to misrepresentation by omission in brain injury diagnosis. What about Cranial Nerve I?
Myers, for all his failure to “get it”, tested Cranial Nerve I and tested it thoroughly. Cranial Nerve I is the olfactory nerve, the nerve which comprises most of the human sense of smell. If all neurologists would so diligently test Cranial Nerve I (and unlike Myers understand its significance) the quality of brain injury diagnosis would go up exponentially.
What is the relevance of the loss of smell to a diagnosis of brain injury? To fully appreciate this, it is necessary to understand the basic geography of the brain and the cranial nerves. The cranial nerves are generally the nerve groups which control the function of muscles, organs and feelings in the head (the cranium). For example, Cranial Nerve VII is needed to make a person smile. Cranial Nerve VIII is involved in balance and the vestibular system. Cranial Nerve I is the Olfactory Nerve, which is responsible for the sense of smell. For a full chart of the Cranial Nerves see: http://www.gwc.maricopa.edu/class/bio201/cn/cranial.htm
Understanding the Geography of the Olfactory Nerve
Unlike the other Cranial Nerves, which take a circuitous route into the brain through the brainstem, Cranial Nerve I goes directly from the nose into the brain. At the juncture between the Olfactory Nerve and the brain is something called the Olfactory Bulb. Immediately adjacent to the Olfactory bulb, on the surface of the brain, are some of the most sensitive and important functions of the lower frontal lobes. While losing the sense of smell does not mean that a person has brain damage, when the Olfactory Nerve is injured in a traumatic event, there is in most cases, correlative damage to the adjacent structures of the brain. That particular part of the brain is the orbital frontal lobe.
Loss of Smell not an Anomaly but Sign of Brain Injury
Thus, when Myers was meticulously documenting the loss of smell in his patients, he was not describing an anomaly, but very significant correlative damage to the part of the neurological system, immediately adjacent to some of the most sensitive and important parts of the brain. The predictive value of loss of smell to brain injury pathology is born out by substantial research that correlates disability to loss of smell. See Neuropsychological Significance of Anosmia following Traumatic Brain Injury
Journal of Head Trauma Rehabilitation. 14(6):581-587, December 1999.
Callahan, Charles D. PhD, ABPP; Hinkebein, Joseph PhD http://www.headtraumarehab.com/pt/re/jhtr/abstract.00001199-199912000-00006.htm;jsessionid= LNTQj0tnvkKKVQB1Z2yMGwZphHLhQh2Q21TSY4HLQnCw8pFLyTlS! 435538499!181195629!8091!-1 and Varney NR, Pinkston JB, Wu JC. Quantitative PET findings in patients with posttraumatic anosmia. J Head Trauma Rehabil. 2001;16:253–259. Such correlation is stronger than almost any other marker of brain injury with the exception of amnesia.
Loss of Smell is Called Anosmia
The technical term for loss of smell is anosmia. As most neurologists do not test for loss of smell, it is often necessary to look for clues that anosmia occurred. The best clues to anosmia are typically changes in taste, eating habits and weight. Smell is a big part of how people taste, especially the subtle differences between foods. Post traumatic anosmia fundamentally changes how and what people taste. This can leave the marker of weight loss – or the more common – weight gain. Those with anosmia often increase the fat content and the spice content of their food, in order to have it taste more.
King Henry the VIII’s remarkable gain in weight after his jousting injury (and significant loss of consciousness) is probably best explained by anosmia. His patterns of neurobehavioral changes after such injury clearly correlate to frontal lobe injury. See http://waiting.com/blog/2008/06/henry-the-viii-and-brain-injury-behavior-changes.html
While Myers’s case study does not include any longitudinal study of either change in weight or future employability of his subjects, longitudinal research done with Vietnam vets, clearly documents those phenomenon. If an injured individual has a dramatic change in diet or weight post accident, brain injury must be considered to be part of the diagnostic differential. Of course simply testing for loss of smell works, too.Next Understanding the Biomechanics of War Time Brain Injuries