Neuroplasticity and Alzheimer’s
This morning I read a fascinating article published yesterday in the New York Times by Helen Santoro, “The Curious Hole in my Head.” Ms. Santoro had some worrying neurological findings at birth prompting a brain scan. This revealed a large space in her cranial cavity where the left temporal lobe of her brain should have been. This was most likely due to an in utero stroke well before she was born. Most children with this condition have significant neurological impairment as they grow older, but Ms. Santoro surprised the experts, “meeting all of the typical milestones of children my age. I enrolled in regular schools, excelled in sports and academics. The language skills the doctors were most worried about at my birth — speaking, reading and writing — turned out to be my professional passions.” How could this be? The left temporal lobe is one of most important centers for processing language.
This case sheds an interesting light on the concept of neuroplasticity, the ability after brain injury to repair the hardwiring in the brain via the growth of new neurons and synaptic connections. In addition, neuroplasticity can involve the reprogramming of intact neural circuits so that they can take on new jobs. When I was a neurology resident in the 1980s, we were taught that neuroplasticity was only possible during childhood. Indeed, the most amazing case I saw was when I was rotating on the pediatric neurology service and saw an 11-year-old girl who had had the entire right side of her brain removed 7 years previously in a desperate attempt to control intractable and life-threatening seizures caused by Rasmussen’s encephalitis. Although she had spasticity on the left side of her body, she was able to walk and use both arms. The left side of her brain had taken over a lot of the function of the missing right side. Neuroplasticity in children allows remarkable reassignment of brain function after removal of diseased brain.
Removal of an entire brain hemisphere in an adult would not have such a good outcome. The result would almost certainly be a total paralysis of the side of the body opposite to the hemispherectomy. Although neuroplasticity is not as robust in adults as it is in children, we now know that it exists. It is in part responsible for recovery after strokes, particularly the small ones. It also appears to be important in slowing the advancement of cognitive impairment in Alzheimer’s disease. I wonder if neuroplasticity may play a role in promoting cognitive reserve. Work is now underway to determine if the mitigation of reversible risk factors for Alzheimer’s may operate in part through enhancement of neuroplasticity.
Thank you for sharing this. At the end of your post you mention that work is underway to determine if mitigation of reversible risk factors may operate in part through neuroplasticity and I look forward to hearing more. I’m assuming risk factors such as lower level of education and isolation or lack of socialization could be mitigated in a way which would involve using the brain and possibly utilizing neuroplasticity? I’m wondering whether neuroplasticity or the ability for the brain to more readily utilize its own neuroplasticity is influenced by diet and exercise? I think back to the nun study you described in your book and I have since read a theory that sometimes people with high cognitive reserve may be diagnosed later because they have actively built alternative neuro pathways as part of ever day life by remaining brain active. II look forward to learning more. Thank you Dan. Much appreciated. Leslie