A stroke occurs when the blood supply to an area of the brain is temporarily or permanently lost. A brain artery blockage or rupture causes a stroke, also called a cerebrovascular accident or CVA. The brain stem connects the brain to the spinal cord. It controls heart rate, breathing, blood pressure and carries the messages between the higher areas of the brain and the body. A brain stem stroke can affect vision, hearing, movement, posture, heart rate, breathing and blood pressure.
Paralysis
A brain stem stroke can cause loss of nearly all voluntary movement possibly sparing only eye control. The sufferer is conscious and able to think normally but is unable to move or communicate. This condition is called locked-in syndrome. People with less severe brain stem strokes may have varying degrees of weakness or paralysis of the arms and legs. The severity of symptoms depends on the exact location of the stroke and whether blood flow was quickly restored to the affected area.
Speech Impairment
Speech is commonly affected by a brain stem stroke. In the most severe cases, the ability to speak is lost. In less severe strokes, coordination of the muscular movements of the mouth and tongue are impaired causing difficulty making the sounds to speak. Hoarseness is common in those who are still able to speak.
Breathing Impairment
The brain stem contains the respiratory drive center, which controls breathing. A massive stroke-related injury to the brain stem can destroy this area. People with this injury require a ventilator to mechanically control their breathing. In less severe brain stem strokes, the respiratory drive center is injured but not destroyed. Sleep apnea--periods where breathing stops during sleep--may occur. Breathing may be shallow or slow during waking hours.
Eating Difficulty
The brain stem controls the coordination of chewing and swallowing. A stroke in this area may cause eating difficulties due to the inability to chew and swallow food without choking. A feeding tube placed into the stomach provides nutrition if eating is not possible.
Coordination
The brain stem plays an important role in coordinating voluntary movement. Stroke-related brain stem injury can severely impair coordinated muscle movement. The ability to walk can be lost or impaired even without paralysis because of lost capacity to control leg muscle movements. Standing or sitting up may be impossible because even these static postures require coordinated muscle control.
Eye Movement Abnormalities
Eye movement control is primarily located in the brain stem. A stroke in this area may cause loss of voluntary control of one or both eyes. Without brain stem input, the eyes shift back and forth without the capacity to maintain focus on any given object.
Unstable Heart Rate and Blood Pressure
Brain stem stroke may injure or destroy the areas of the brain that control heart rate and blood pressure. The heart rate may be irregular and the blood pressure unstable.
Vertigo
Loss of balance and a sensation of twirling (vertigo) are common symptoms of brain stem stroke. Vertigo typically causes persistent nausea.
