Elsberg1 has recently described a new method for the physiologic and clinical study of olfaction. The instruments and the procedure used have been described by him,2 and we have followed his technic in detail. His most important methods for clinical purposes consist in determination of (1) the minimal identifiable odor, or the smallest amount of air mixed with odor, expressed in cubic centimeters, necessary for recognition on one side of the nose and (2) the "olfactory fatigue," which is the refractory period elapsing after a certain degree of fatigue has been produced until the odor can again be perceived. Elsberg found an increase in the value for the minimal identifiable odor in cases of cerebral tumor which produces direct or indirect pressure on the olfactory tract and an increase in olfactory fatigue on the same side as the lesion in cases of tumor within the cerebral hemisphere.
Adler A, Finley KH. CLINICAL RESULTS WITH ELSBERG'S OLFACTORY TEST. Arch NeurPsych. 1938;40(1):147-150. doi:10.1001/archneurpsyc.1938.02270070157011