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Monday, April 01, 2002  Shock Waves:   A Scientist Studies His Stroke  By: J. Allan HobsonM.D. [continued]

BRAIN DAMAGE, NATURAL AND EXPERIMENTAL 

When researchers make a surgical lesion in the brain of an experimental animal, we almost certainly produce both primary effects (neuronal death) and secondary effects (neuronal dysfunction) of the kind that my stroke caused. As I mentioned when describing my early hospitalization, I knew that transection of a cat’s medulla at the mediopontine level produces an intense insomnia lasting about 10 days; normal sleep is recovered over the next 20 days. The more time that passes, the greater the recovery of function, the compensation for function, or both. We cannot know if this is simple recovery and compensation, which imply brain plasticity. But it seems probable, both from my own studies and from reports on other research, that the explanation of the insomnia is far less likely to be the disenabling of a supposed synchronizing mechanism in the lower brain than it is to be secondary damage to the areas of the brain adjacent to the primary lesion. 

The moral: We must be cautious in drawing inferences about relationships between structure and function. Before concluding that a given sleep stage, with its associated mental experience, has been eliminated by a lesion, we need much longer observation than most experimenters have invested. We also need more searching psychological probes than neuropsychologists have used until now. When it comes to functions like dreaming, for which we rely on subjective reports, a subject’s ability to report may be intact—although, in my case, gross oversleeping during the rehabilitation proved an obstacle to dream recall and reports. Of course, we also need objective recordings to corroborate subjective reports. Did I really recover my REM sleep? Was it the same as my pre-stroke REM sleep? These are important questions. 

The only aspects of my consciousness that needed to be rehabilitated after my stroke were the comfort of sleep and the experience of dreaming. My reports substantiate that my cognitive functions were not only intact but extended: After all, I spent far more time awake than normal— noticing, recording, and analyzing my mental and physical states. 

While still in the hospital in Monaco, as soon as my double vision ceased, I began editing manuscripts and page proofs. It felt good to be productive again. Also, I could watch television once more, because only one screen appeared, not two. When the beloved French singer-songwriter Charles Trenet died, I was thrilled to hear his great chansons, see him in interviews, and realize how great an impact he and the France of his chansons had on my life. I learned to speak French in high school but I learned what it is to be French during my year in Michel Jouvet’s lab in Lyon in the 1960s. That was where we made medullary lesions in the brain stems of cats and observed intense mania. Since then, I have felt that a part of me was French. Deciding to stay in Monaco instead of flying home immediately after my stroke reflected my comfort with the French hospital. 

Before I left Monaco, two women friends traveled all the way from Bordeaux to visit me. This expression of love buoyed my spirits. My survival and recovery were enhanced enormously by the support of a far-flung social network. Via e-mail, telephone, fax, and airmail, I was in touch with colleagues and friends from around the world and from earlier epochs of my life. This communication continues to enrich me, and I hope that this account may put me in touch with still more people who know my work or have shared some of these experiences. 

All in all, I felt extraordinarily positive about my future, and utterly unprepared for what autumn would bring. 

As my brain healed (or perhaps just settled down), I slept better—at times too much, slowing my efforts to relearn how to walk. This prompted my doctor at Spaulding Rehabilitation Hospital to put me on Ritalin as a stimulant, although I mightily resisted the suggestion out of fear of becoming addicted. After a month of painful daily practice, I could walk with a cane and go home to my family. Shortly thereafter, I threw away the cane. On April 16, I was home, in my own garden, happily celebrating the fifth birthday of my twin sons. 

SECOND WAVE 

In the months following my discharge from Spaulding, I reclaimed my life and enjoyed a wonderful summer. I gloried in resuming an almost full range of activities, traveling to Sicily with Lia on June 16 to spend the summer in our apartment in Messina. This included, in late June and early July, a beautiful vacation in Stromboli. 

In Messina, I completed a first draft of A Short Introduction to Dreaming for Oxford University Press. It was fun to write, but above all reassuring to show that I could function as I always had, writing in the morning in my office in Messina or on the dining porch at the Hotel Miramare in Stromboli. I even made a good start on Experimental Animal, a book about my life and my dreams. Lia and I enjoyed social activities, including dinners and long weekends with friends. Adding to the excitement, we had the opportunity to hear Bob Dylan in concert in Taormina. All in all, I felt extraordinarily positive about my future, and utterly unprepared for what autumn would bring. 

Not that all my symptoms had vanished. In Messina, I tried to wean myself off the 20 mg daily dose of Ritalin I had been taking since early April, but I simply could not make the cut from 10 to 5 mg without my motor system reacting. I was almost incapable of initiating movement until I went back to up 20 mg. The telephone in our hallway would ring four times before I could struggle out of my chair. 

In retrospect, it may have been wise to trust my instinct to resist going on Ritalin in the first place. I wonder if my cardiovascular and cardiopulmonary motor system became dependent on this externally applied dopamine-like agent. On the other hand, perhaps my withdrawal from the drug was not gradual enough. In two attempts, I spent four days at each drug level—20, 15, 10, 5, then 0—as I withdrew. Thus complete withdrawal occurred in four steps over two weeks. The second time I had no particular difficulty, so it is unclear what contribution Ritalin or withdrawal from it made to the events that followed.