but her body rejected every one of those . Later she had a successful transplant with the use of antirejection drugs , but a freak accident led to injuries to the eyes , depriving her of vision permanently . She started having visual hallucinations that were initially patterns and shapes , but later evolved into faces , often scary with “ blood from their eyes and gnarly teeth .” Dr . Leschziner delves into the history and features of Charles Bonnet syndrome , named after the author of an essay in 1760 , describing the story of his 90-year-old grandfather , who lost his vision and started experiencing vivid hallucinations of people , animals , buildings , tapestries , etc . One interesting feature was seeing small people , termed Lilliputian as in Jonathan Swift ’ s Gulliver ’ s Travels . Dr . Leschziner analyzes the neural basis of Charles Bonnet syndrome from the simplistic concept of “ the brain ’ s desire to see even in the absence of vision ” to the more complex theories .
Chapter 3 named The Stench of Rose deals with the sense of olfaction . I particularly liked Dr . Leschziner ’ s description of the olfactory system : “ Unlike many other parts of the nervous system , these olfactory neurons are constantly regenerating , lasting on average a month or two before being replaced by continuously replicating stem cells .” He continues to elaborate on the unique role of the olfactory system : “ The whole world studied through a single breath . Underlying this examination of the universe is the only point where the central nervous system meets the outside world , where our brain reaches out beyond the confines of our bodies .” He discusses the 2004 Nobel prize-winning work by Linda Buck and Richard Axel , who identified a large family of genes that are responsible for detecting the volatile airborne chemicals dissolved by the lining of the mucosa - otherwise known as olfactory receptor genes . He goes into more details of how 370 olfactory receptors that we have ( as compared to the mice ’ s 1,100 ) can detect thousands of smells .
The more interesting part of the chapter is the case of Joanne , who developed severe parosmia after a protracted upper respiratory infection . He quotes her “ I started to notice a really bad distorted smell . I could not put my finger on it . It could be between rotting fish and sewage . Really foul putrid smell .” She became depressed and withdrawn and “ just wanted to sleep all the time because that was my only escape .” After years of suffering , she regained her sense of smell and believes that it was due to treatment with theophylline and gabapentin .
Dr . Leschziner devotes a chapter explaining the sensation of taste and its role in the perception of flavor with several anecdotal cases . However , the most fascinating chapter is the one that deals with synesthesia , apparently due to “ cross talk ” between different sensory pathways . He describes a patient in whom sound / words were associated with specific taste and texture ( gustatory synesthesia ). The book title is based on one such a patient who “ tasted words .” A similar phenomenon has been described in which words and letters are seen in color . Several cases with different forms of synesthesia are described by the author with explanations of the underlying neurophysiologic process .
The Man Who Tasted Words is a fantastic book and no matter what your medical specialty is , you will enjoy it . I will end with a quote from that book : “ The pathway to perception is a two-way street . Our ultimate experiences are a balance between sensory inputs coming in and our internal model of the world , a delicate equilibrium between ‘ bottom-up ’ and ‘ top-down ’ flows of information .”
Dr . Iyer practices at the Neurodiagnostic Center of Louisville and is a retired professor of neurology at the University of Louisville School of Medicine .
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