Medicine: MIO

Surgeons in plays and cinemas who whisper “Brain tumor!” behind the doomed victim’s back give laymen the impression that these disorders are rare. But Dr. Harvey Williams Gushing, famed Yale brain surgeon, declares that no part of the body, with the possible exception of the uterus, is as troubled by such malignant growths as the brain. Dr. Gushing has made the acquaintance of more than one thousand brain tumors and one of the commonest, most rapidly growing and most immediately fatal types—the spongioblastoma—comprises one-third of his cases. Surgical removal is sometimes effective but there is desperate need of early diagnosis. Last week Dr. Charles Albert Elsberg of Manhattan’s Columbia-Presbyterian Medical Centre reported a diagnostic technique for brain tumor which he deemed more sensitive than any other currently employed. Dr. Elsberg’s way is to test the patient’s sense of smell.

He was aware, like other experimenters, that cerebral tumors frequently nudge the olfactory centres of the brain, blunt the sense of smell. But sharpness of smell is so inconstant and the weak human nose can detect such minute quantities of a substance, that precise measurement seemed hopeless. Then Dr. Elsberg tried having the subject hold his breath while whiffs of air saturated with coffee or lemon oil from a stoppered flask were pumped up the nostrils, directly against the ends of the olfactory nerves. He found that in normal persons a fairly constant and easily measurable quantity of scent-laden air was necessary to produce an impression. For coffee it was eight to nine cubic centimetres, for lemon oil six to eight. These quantities he labeled “MIO”—minimum identified odor.

For every subject known to have a brain tumor, or subsequently found to have one, of whatever size, the MIO was definitely higher than normal. Olfactory fatigue (individual increase of MIO after prolonged whiffing) was also longer than normal. Extent to which the MIO and fatigue were abnormal furnished a rough clue to the size and depth of the tumor. Finally, unequal distribution of scent power andendurance between the two nostrils showed that the tumor was located wholly or mostly in one hemisphere of the brain.