V V: Uncommon senses

Oliver Sacks, the foremost interpreter of neurology for a reader, has transformed the relationship between brain and mind into an almost literary one. In his classic work, The Man Who Mistook his Wife for a Hat, published over 25 years ago, Dr Sacks had said in his introduction that neurology’s favourite word was “deficit”, denoting an impairment or incapacity in neurological function: loss of speech, loss of language, loss of memory, loss of vision, loss of dexterity, loss of identity, “and myriad other lacks and losses of specific functions or faculties”. In his 11th book, The Mind’s Eye (Picador, Rs 535), he has continued with his study of “deficits” or our sensibilities dulled by what the evolutionary biologist Richard Dawkins describes as “the anaesthetic of familiarity”. But this time, Dr Sacks takes vision and visual imagination as his basic theme, mixing case histories, essays and memoirs to show “what is often concealed in health, the complex workings of the brain and its outstanding ability to adapt and overcome disabilities”.

There are seven essays in the book: “Sight Reading”, “Recalled to Life”, “A Man of Letters”, “Face-Blind”, “Stereo Sue”, “Persistence of Vision: A Journal” and “The Mind’s Eye”. All deal with vision or sight gone awry. The first three are about the neurology of language and reading; the last four are about the neurology of perception. Neither are the two sections linked to each nor do they spell out any underlying theme. They are stories, though there are occasional attempts at explaining the variety of symptoms he describes. But the serious common reader is really interested in the richness of the experiences and the oddities of the phenomena presented. Implicit in Dr Sacks’ panorama of the classical problems is a deep understanding of reading, perceiving and understanding.

The first half of the book is dominated by one of the most famous neurological cases in medical history that was described in 1892 as “different kinds of verbal blindness” or an inability to read with “faded and colourless vision on the right side”. The patient was 68 years old and had always been in excellent health. He led a happy married life, frequently played music, was well informed about literature and read a great deal.

One day he had a series of attacks of numbness on his right leg but this did not particularly hamper his lifestyle till he realised he couldn’t read a single word. Yet, he was able to speak and write and had no difficulty in recognising objects or people. Thinking he needed reading glasses, his wife consulted an ophthalmologist. The patient said he could figure out every letter on the eye chart but he couldn’t read them. With great difficulty he could write each letter but he still couldn’t read what he had written.

It was much the same with figures. “When shown the number 112, he could write 1, a 1 and a 2. But he couldn’t read the multi-digit number unless it was written down.”

After the patient’s death, his wife had an autopsy done. It revealed that “the visual centres of his brain were disconnected from the language centres”, which is why, Dr Sacks says, patients with stroke lesions see letters and words as “drawings” rather than language symbols.

Howard, a crime novelist, suffers from the same condition. How could he write another detective story if he couldn’t read his own plot notes? Another patient, Pat, suffered a stroke and lost the power of speech. She doesn’t have a perpetual disorder but she remains aloof from people and is, therefore, considered a little eccentric. In Stereo Sue, she sees the world only in two dimensions until her 50s. The gift of depth analysis is simply beyond her. “Enough thinking,” she tells Dr Sacks at one point.

Dr Sacks is very good at showing the resourcefulness of embattled brains for which he is indebted to the famous Russian neurologist A R Luria, the author of two classic works, The Mind of a Mnemonist and The Man with a Shattered World. These show how the cross-wiring of the brain helps take over the functions of the damaged part. (Dr Sacks generously acknowledges the contributions of famous neurologist V S Ramachandran in understanding the human mind.) He shows here how Howard, for example, discovers the complementarity of vision and action when he realises that tracing the outlines of words with his tongue remarkably improves reading comprehension. “This by an extraordinary, metamodal, sensory-motor alchemy he was in fact reading with his tongue.” And he goes on to write another novel!

In his lead essay, “The Mind’s Eye”, Dr Sacks raises the question that all of us would ask: “To what extent are we the authors, the creators, of our own experiences? How much are these predetermined by the brains or senses we are born with, and to what extent do we shape our brains through experience?” Dr Sacks attempts to answer these questions but these lead to another question: is consciousness determined by structures of the brain (the brain is fairly well-mapped-out now) or is there something unknown that we can’t account for? As Shakespeare wrote in Hamlet, “There are more things in heaven and earth/Than are dreamt of in your philosophy.”