What Are The Signs Of Subclavian Steal Syndrome?

Dysarthria

Dysarthria is a condition where an individual has weaknesses or problems with controlling the muscles they use to create speech. Dysarthria has been described to be similar to speech that is slowed or slurred and is hard to understand. An individual who experiences dysarthria may be unable to speak loud enough or may speak too loudly. They may also exhibit an abnormal or uneven speech rhythm or volume. A patient who has dysarthria may speak in a monotone or have a raspy, nasal, or strained voice.

Dysarthria can occur in subclavian steal syndrome patients due to the mechanism triggered by the circle of Willis when the subclavian artery becomes obstructed. The circle of Willis redirects an individual's blood from their brain tissues to the arm lacking circulation by using the vertebral artery. This mechanism causes some of the brain tissues to be starved of oxygen, causing them to be unable to function. When the blood is stolen from the part of the brain that controls the muscle responsible for producing speech, the patient will experience dysarthria.

Dysphagia

Dysphagia occurs when an individual experiences difficulty with swallowing. Swallowing is a mechanism with three different steps and requires the participation and coordination of the muscles in the pharynx, mouth, and esophagus. The group of nerves in the brain that controls these muscles is referred to as the cranial nerves. The cranial nerves are a series of twelve pairs of nerves that branch off from the brainstem at the base of the brain. Tasting, smelling, seeing, moving the face, moving the eyes, shrugging the shoulders, and swallowing are all functions controlled by the cranial nerves.

The swallowing mechanism involves several cranial nerves, including the trigeminal, glossopharyngeal, hypoglossal, facial, and vagus nerves. A subclavian steal syndrome patient may experience malfunctions in these nerves and the precentral gyrus of the brain when the circle of Willis pulls blood from these structures to the arm that is lacking. The shortage of oxygen from poor blood flow causes the cells that control the swallowing centers in the brain and the cranial nerves to shut down, producing dysphagia.