Olivopontocerebellar atrophy

Olivopontocerebellar atrophy is a group of genetic diseases in which there is progressive degeneration of the olivopontocerebellar pathway in the brain connecting the inferior olive, pons, and cerebellum. The cerebellum is the part of the brain that plays a role in maintaining balance and posture as well as coordinating voluntary movement.

The pons is part of the brainstem and contains important neuronal pathways between the cerebrum, spinal cord, and cerebellum. The pons serves as a relay point for messages between these structures. The inferior olives are two round structures that contain nuclei that are involved with balance, coordination and motor activity.

Olivopontine cerebellar degeneration may occur sporadically or as an autosomal dominant trait. It is characterised by a general atrophy of the cerebellum spreading in time to involve the pons, medullary olives and other brain stem structures. It can occur at any age but onset in middle life is most common. Presentation is initially with ataxia, dysarthria, and tremor. Parkinsonian features may develop, accompanied by mild dementia, ophthalmoplegia, pyramidal tract signs and autonomic disturbance.

Olivopontocerebellar atrophy can be inherited but it most commonly affects people without a known family history (sporadic form). Sporadic cases tend to affect people in their 50s while familial cases usually start earlier. The cause of sporadic olivopontocerebellar atrophy is not known, but the disease is progressive.

Many symptoms are associated with olivopontocerebellar atrophy but the predominant feature is progressive ataxia (clumsiness) and difficulties with balance. There may be slurring of speech and difficulty walking. A thorough medical and neurological examination as well as a good history of symptoms and family history are necessary to make the diagnosis. There are no specific tests for this condition.

An MRI of the brain may show a small cerebellum or brainstem, or atrophied olives. This is helpful in making the diagnosis but lack of these findings do not necessarily rule this condition out. Other tests may be done to rule out other diagnoses. Swallowing studies can be done to evaluate a patient's ability to swallow food and liquid safely.

There is no specific treatment or cure for this disease. Therapy is aimed at supportive care and prevention of complications. This may include evaluation of swallowing and use of techniques to prevent choking; speech and physical therapy, and use of walking aids to help with balance and prevent falls.