Jan. 25, 2000 ST. PAUL, MN -- Is the ability to sneeze taken for granted? Stroke patients who lost the ability to sneeze each time they felt a familiar ticklish feeling in their noses may think so.
In the current issue of Neurology, a researcher identified four people recovering from strokes who temporarily lost the ability to sneeze even though the urge to sneeze and the ability to mimic the action remained. Each person had a stroke affecting the left or right side of the lower brain stem, an area of the brain known as the medulla, according to a case report in the January 25 issue of Neurology, the scientific journal of the American Academy of Neurology.
"I first noticed this symptom when one of my stroke patients expressed considerable frustration that he could not sneeze," said neurologist and study author Mark Hersch, MD, PhD, of New South Wales University and St. George Hospital, both in Sydney, Australia. "When the patient felt the ticklish feeling in his nose signaling a sneeze, the build up would peter out before the explosive completion of the sneeze, leaving him feeling dissatisfied. One year later the patient was delighted to tell me that he could sneeze again."
Hersch reports that three other patients with strokes affecting the medulla had the same problem. In each case the build-up to the sneeze was not affected, only the completion of the sneeze. These three people recovered the ability to sneeze within six months.
Sneezing is a reflex designed to protect the body's respiratory system. It requires sensory input (a ticklish feeling in the nose) to start the sneeze. The ticklish sensation in the nose connects to nerves that initiate the final action, which is a rapid exhalation through the nose and mouth. Typically, once the sneezing reflex is triggered, the final action occurs automatically. In the case of these patients, the automatic ability to link the ticklish feeling in the nose to the final sneeze was temporarily impaired, said Hersch.
In these cases only one side of the medulla was affected by the stroke. This suggests that both the left and right side of the medulla must be intact for the sneezing reflex to occur, Hersch said.
The number of patients who lose the ability to sneeze after strokes affecting the medulla is not documented. "I assume that many patients with this type of stroke lose the ability to sneeze temporarily, but fail to tell their doctor," said Hersch. "Some of my patients have been amazed and relieved to hear that other patients have experienced the same symptom.
"Aside from being frustrating, the inability to sneeze will not cause other medical conditions. I do recommend avoiding dusty environments until the sneezing reflex returns to normal."
Literature suggests that the most common cause of unexplained inability to sneeze is psychiatric. A tumor on the medulla can also affect the ability to sneeze.
A neurologist is a medical doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system.
The American Academy of Neurology, an association of more than 16,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research.
For more information about the American Academy of Neurology, visit its Web site at http://www.aan.com. For online neurological health and wellness information, visit NeuroVista at http://www.aan.com/neurovista.
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