Congenital bilateral perisylvian syndrome

Overview

Congenital Bilateral Perisylvian Syndrome (CBPS) is a rare neurological disorder characterized by abnormal development of the cerebral cortex, particularly in the perisylvian region of both brain hemispheres. This region is important for speech, swallowing, and motor control of the face and mouth. Individuals with CBPS typically present with a constellation of symptoms including oromotor dysfunction, epilepsy (often difficult to control), and varying degrees of intellectual disability and motor impairments. The disorder is considered a type of neuronal migration disorder, meaning the brain cells did not move to their proper positions during fetal development.

Causes

CBPS is believed to be caused by genetic mutations or developmental disruptions affecting neuronal migration during early fetal brain development. The exact cause is not always known, but potential contributing factors include:

• Genetic mutations: Mutations in genes involved in cortical development (e.g., SRPX2, EOMES) have been implicated in some cases

• Sporadic (non-inherited) mutations: Many cases occur without a family history and are believed to arise de novo

• Environmental or prenatal factors: Such as intrauterine infections, vascular insults, or exposure to toxins during gestation may play a role

In most cases, the condition is congenital and non-progressive, although symptoms may evolve with age.

Symptoms

The severity and combination of symptoms can vary significantly, depending on the extent of cortical malformation. Common symptoms include:

• Oromotor dysfunction: Difficulty with chewing, swallowing (dysphagia), and speech articulation (dysarthria)

• Pseudobulbar palsy: Involuntary movements of the face, tongue, and throat due to corticobulbar tract involvement

• Seizures: Often severe and resistant to standard antiepileptic medications

• Intellectual disability: Ranging from mild to severe cognitive impairment

• Developmental delay: Especially in speech, motor milestones, and coordination

• Spasticity or hypotonia: Muscle stiffness or weakness, especially in the face and limbs

• Drooling and feeding difficulties: Due to poor oral motor control

• Facial diplegia: Bilateral facial weakness may be present

Diagnosis

Diagnosis of CBPS is based on clinical presentation and confirmed with neuroimaging. Diagnostic steps include:

• Neurological examination: To assess oromotor function, motor tone, reflexes, and developmental progress

• Magnetic Resonance Imaging (MRI): Reveals polymicrogyria (excessive small brain folds) in the bilateral perisylvian region

• Electroencephalogram (EEG): To detect seizure activity and guide epilepsy treatment

• Genetic testing: May identify underlying mutations or syndromic associations

• Swallow study and speech evaluation: To assess oromotor dysfunction and feeding issues

Treatment

There is no cure for CBPS, so treatment focuses on managing symptoms and improving quality of life through a multidisciplinary approach. Key components include:

• Antiepileptic medications: To control seizures, although seizures may be drug-resistant in many cases

• Speech and language therapy: To improve communication and address dysarthria or anarthria

• Feeding therapy: To assist with swallowing difficulties and reduce the risk of aspiration

• Physical and occupational therapy: To support motor development and functional independence

• Special education services: Tailored learning plans to accommodate cognitive and communication delays

• Surgical interventions: May be considered for intractable epilepsy (e.g., focal resection or corpus callosotomy)

• Gastrostomy tube (G-tube): May be necessary for individuals with severe feeding issues

Prognosis

The prognosis for individuals with Congenital Bilateral Perisylvian Syndrome varies depending on the severity of brain involvement and associated complications. Many individuals require lifelong supportive care and have significant challenges with communication, feeding, and mobility. However, early intervention and consistent therapy can improve functional outcomes and quality of life. Seizures may be difficult to control, and intellectual disability can limit independence, but with appropriate care and support, many patients can achieve meaningful progress in their daily lives.