Pseudobulbar palsy

Pseudobulbar palsy is a medical condition characterized by the inability to control facial movements (such as chewing and speaking) and caused by a variety of neurological disorders. Patients experience difficulty chewing and swallowing, have increased reflexes and spasticity in tongue and the bulbar region, and demonstrate slurred speech (which is often the initial presentation of the disorder), sometimes also demonstrating uncontrolled emotional outbursts. The condition is usually caused by the bilateral damage to corticobulbar pathways, which are upper motor neuron pathways that course from the cerebral cortex to nuclei of cranial nerves in the brain stem. Signs and symptoms of pseudobulbar palsy include: Slow and indistinct speech Dysphagia (difficulty in swallowing) Small, stiff and spastic tongue Brisk jaw jerk Dysarthria Labile affect Gag reflex may be normal, exaggerated or absent Examination may reveal upper motor neuron lesion of the limbs Pseudobulbar palsy is the result of damage of motor fibers traveling from the cerebral cortex to the lower brain stem. This damage might arise in the course of a variety of neurological conditions that involve demyelination and bilateral corticobulbar lesions. Examples include: Vascular causes: bilateral hemisphere infarction, CADASIL syndrome, artery of percheron infarct Progressive supranuclear palsy Amyotrophic lateral sclerosis Parkinson's disease and related multiple system atrophy Various motor neuron diseases, especially those involving demyelination Multiple sclerosis and other inflammatory disorders High brain stem tumors Metabolic causes: osmotic demyelination syndrome Neurological involvement in Behçet's disease Brain trauma The proposed mechanism of pseudobulbar palsy points to the disinhibition of the motor neurons controlling laughter and crying, proposing that a reciprocal pathway exists between the cerebellum and the brain stem that adjusts laughter and crying responses, making them appropriate to context.