Cortical Malformations

Malformations of cortical development (MCD) is a condition where the cortex sequence is altered during the formation of the brain. The cortex is the outer layer of the brain, often described as looking like the folded, wrinkly tissue. It is also the largest part of the brain and controls higher thought, speech and decision making. 

The cortex is a collection of neurons divided into four sections, or lobes, which are each responsible for different functions of the body and mind. The cortex grows and changes throughout life, but the neurons come into formation and sequencing during the first two months of embryonic growth.

While the exact cause of MCD is unknown, it is suspected that during the first two months in-utero, certain neurons are incorrectly sequenced or have a presence of abnormal neurons. The poorly placed neurons cause one side of the brain to grow irregularly. MCD is sometimes referred to as cortical dysplasia. In addition to irregular growth, MCD causes irregular electrical activity and as a result, epileptic seizures.

Symptoms

MCD typically causes developmental delays and seizures, although the type of seizures tends to vary depending on the patient’s age.

• Focal seizures
• Developmental delays beginning as early as 3 months old
• Cognitive deterioration

Causes

While the exact reason MCD occurs in the brain is unknown, it is generally thought that either genetics or environmental factors play a role.

Diagnosis

If MCD is suspected, a detailed evaluation by a neurologist will be necessary. During the neurological evaluation, an MRI, CT scan or EEG may be conducted.

• MRI: An MRI uses large magnets, radio waves and a computer to produce a map of the brain.
• CT scan: This test uses a series of X-rays and a computer to create images of the inside of the body. A CT scan shows more detail than a regular X-ray.
• EEG: This test records the brain's electrical activity through sticky pads (electrodes) attached to the scalp.

Treatment

The effects of MCD may be treated with either pharmacological therapies or in some cases, surgery.

• Medication: A neurologist will prescribe pharmacological therapies to maintain and control seizures.
• Surgery: Surgery to treat MCD includes focal resections and hemispherectomies. The surgeries both involve removing a part of the brain. For young children who receive this surgery, the healthy part of the brain may grow and take over the functions of the resected section. This is known as plasticity.

Additional Resources

• National Institute of Health