Polymicrogyria (PMG)

Approximately 90% of persons with polymicrogyria develop seizures at some point in their life, and most of these will begin in childhood. In those who do develop epilepsy, several types of seizures can be seen, based upon the location, severity, and type of disorder itself.

Polymicrogyria affecting a smaller area of one hemisphere (side of the brain) often presents with focal seizures in children or slightly older individuals, many of whom have been otherwise healthy. Sometimes these focal seizures can spread to involve both sides of the brain and thus appear a generalized tonic-clonic seizure.

Polymicrogyria that involves one entire hemisphere (side of the brain) is usually associated focal seizures affecting the opposite side of the body that begin in early to mid-childhood, weakness and movement problems on that side of the body, and mild to moderate intellectual disability.

Persons with bilateral polymicrogyria often have atypical absence seizures, tonic or atonic drop attacks and tonic-clonic seizures in addition to focal seizures, and can sometimes present as Lennox-Gastaut syndrome. Some of these babies can also start having infantile spasms earlier in infancy.

Other Symptoms

Common symptoms and other conditions often seen are:

• Cerebral Palsy
• Motor delays
• Cognitive and emotional delays
• Speech delays
• Swallowing problems
• Abnormal head size (too big or too small)

Common cognitive or intellectual disorders connected to PMG include:

• Speech and motor function delays
• Autism
• Behavioral delays
• Dyslexia