How It Can Change Your Mind
Mavis J. Matheson, MD
One of the most frustrating late effects of polio for me was the awareness that I could not concentrate and a feeling that I wasn't thinking clearly any more. For many of us who have compensated for our physical limitations through intellectual pursuits this is a terrifying feeling. Is it not bad enough that our bodies are giving out? Must we undergo the indignity of losing our minds as well? Studies show that in spite of marked impairments of attention, polio survivors are within the high normal or superior range on measures of higher-level cognitive processes and IQ.  They also show that if we allow ourselves to become fatigued we do lose our ability to focus our attention and to rapidly process complex information (requiring 23 to 67 percent more time to complete tasks requiring sustained attention and vigilance than did polio survivors with no fatigue or mild fatigue). 
Polio survivors experience two kinds of fatigue. One is physical tiredness and decreased endurance. The other and often more distressing kind is "brain fatigue". Brain fatigue describes problems with attention, alertness and thinking. Between 70% and 96% of polio survivors reporting fatigue complained of problems with concentration (96%), memory (85%), attention (82%), word finding (80%), staying awake, and thinking clearly (70%).  Tests indicate that an impairment of selective attention (related to damage as a result of polio) results in feelings of fatigue and cognitive problems. 
The poliovirus damages the anterior horn cells of the spinal cord but that is not all it damages. It also damages parts of the brain stem. Findings indicate that poliovirus consistently and often severely damaged the brain areas known as the Reticular Activating System. , These areas are responsible for activating the part of the brain involved in maintaining voluntary attention, memory, spontaneous interest, initiative and the capacity for effort and work, and for preventing feelings of fatigue. This is the area that keeps us awake and allows us to focus our attention. 
Polio survivors report that they are most disabled by the visceral symptoms of fatigue. These are feelings of exhaustion, passivity and an aversion to continued effort that generate an avoidance of both mental and physical activity.  Dr RL Bruno suggests the existence of a Fatigue Generator in the brain.  His findings suggest that there is a close relationship between impaired attention and fatigue. There would be survival value in a brain mechanism that promotes rest when attention and information processing ability are impaired. An area of the brain (the Basal Ganglia) may generate mental and physical fatigue. When the Reticular Activating System is damaged, the Fatigue Generator takes over and produces problems with focusing attention and with physically moving without significant conscious effort. Damage caused by the poliovirus chronically reduces the firing of the nerve cells in the Reticular Activating System. Rest or sleep would increase the firing of the brain activating system nerves, restore activation and once again allow motor behavior.  [Ed: An article by Dr Bruno detailing his work in this area was obtained from the Internet and reprinted in PPN Newsletter Issue 24, June 1995.]
The damage would explain why polio survivors have no difficulty concentrating after the original infection but why are we developing problems thirty or forty years later. One theory is that the age-related loss of nerve cells combined with an already abnormally small number of nerve cells as a result of the original poliovirus infection may impair the brain's activating system enough to produce impaired attention and fatigue as polio survivors reach mid-life. 
The first step in treating the disorders of concentration, memory, attention, word finding, staying awake, and thinking clearly is to deal with the fatigue. Energy conservation, work simplification and the proper provision of rest periods throughout the day are the treatments of choice in dealing with post-polio fatigue.  Stress management is also critical in the treatment of post-polio fatigue.  Dr Bruno et al are currently studying the use of a medication (a post-synaptic dopamine receptor agonist currently used in the treatment of Parkinson's Disease) in the treatment of post-polio patients who do not respond to conservative treatments.  They caution that there is a real danger that treatment with medications will allow Polio survivors to resume their hyperactive Type A lifestyles and further stress poliovirus-damaged, "metabolically vulnerable" neurons in the brain stem and anterior horn. 
As with any treatment strategy we must try to find the most effective treatment that will do the least long term damage while helping us to deal with our current problems. Certainly reducing physical and emotional stresses in our lives and getting adequate rest make sense for everyone, even polio survivors. The good news is if you can get rested, you will find your ability to concentrate, pay attention, remember words and stay awake will improve. You may even find that you can enjoy reading and thinking again!
Bruno RL, Sapolsky R, Zimmerman JR, and Frick, NM. The Pathophysiology of Post-Polio Fatigue: A Role for the Basal Ganglia in the Generation of Fatigue. Annals of the New York Academy of Science, (1994) in press.
Bruno RL, Galski T, DeLuca J. The Neuropsychology of Post-Polio Fatigue. Arch Phys Med Rehabil Vol 74, Oct. 1993.
Bruno RL It's All in your Brain: The cause and treatment of Post-Polio Fatigue, Lecture at Healthy Partnerships Conference Oct. 22, 1994, Toronto, Ont. Canada.
Bruno RL, Frick NM, Cohen J. Polioencephalitis, Stress, and the Etiology of Post-polio Sequelae. Orthopedics. 1991; 14:1269-1276.
Bruno RL, Frick NM, Lewis T, and Creange SJ. The Physiology of Post-Polio Fatigue: A Model for Post-Viral Fatigue Syndromes and a Brain Fatigue Generator. The CFIDS Chronicle Fall 1994.
Young GR. Occupational Therapy and the Post polio Syndrome. The American Journal of Occupational Therapy. 1989; 43:97-103.
Bruno RL, Frick NM. The Psychology of Polio as Prelude to Post-Polio Sequelae; Behavior Modification and Psychotherapy. Orthopedics. 1991; 14:1185-1193.
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