A recent study in Frontiers in Neurology published findings on brain changes in patients with Charcot Marie Tooth disease Type 1A, a rare neurological disease that affects the muscles. The researchers have found the disease causes patients to experience a structural reorganization in the brain, notably, in the cerebellum, the part of the brain controlling balance, and the hippocampus, for memory. They believe this is to compensate for peripheral nervous system imbalances caused by the disease.

Charcot Marie Tooth Type 1A (CMT1A) is a rare neurological disorder caused by a mutation in genes that facilitate communication sensory information to the patient’s muscles. Instead, the mutation causes the nerve cells in charge of communication to deteriorate, impeding communication. Symptoms may begin in adolescence of young adulthood, and include weakness in feet and the lower leg muscles, foot deformities (high arches, hammertoes), leg deformities, hand weakness, muscle atrophy, and difficulty walking or with fine motor skills. There are no cures, but patients have a wide range of therapies that help symptomatically. 

 The brain is able to adapt to changes caused to the peripheral nervous system, the part of the brain that handles communication between the brain and the body, by forming new connects and and rerouting parts of the brain.  Researchers have found that patients with CMT experience brain changes in the peripheral nervous system that they suggest are a mechanism the brain uses to compensate for changes caused by the disease.

The study was done on 40 participants, with 20 healthy subjects matched to 20 CMT1A patients based on demographic attributes. The doctors then examined the variation in the movement and sensory functions both through physical examinations and MRIs.  The MRIs, specifically volumetric magnetic resonance imaging (vMRI) and diffusion tensor imaging (DTI), determined the brain’s internal body in 3D and captured white matter tracts, which are channels of communication between the regions of the brain.

These MRIs picked up on a pattern. Patients with CMT1A tended to have more gray matter, which are mostly made up of nerve cells, in the cerebellum, hippocampus, and parahippocampus. The cerebellum is the brain region responsible for balance and movement, the hippocampus for spatial learning and making memories, and the para hippocampus with memory retrieval.

In the study, they point out how the data is evidence of structural reorganization in CMT1A patients’ brains, which reflects the body’s compensatory mechanism “in response to peripheral nerve pathology.”

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