Anosmia (pronounced ) is a lack of functioning olfaction, or in other words, an inability to perceive odors. Anosmia may be temporary but traumatic anosmia can be permanent. Anosmia is not due to any inflammation of the nasal mucosa; blockage of nasal passages or a destruction of one temporal lobe. It can be caused by chronic meningitis and neurosyphilis that would increase intracranial pressure over a long period of time. Many patients may experience unilateral anosmia, often as a result of minor head trauma. This type of anosmia is normally only detected if both of the nostrils are tested separately. Using this method of testing each nostril separately will often show a reduced or even completely absent sense of smell in either one nostril or both, something which is often not revealed if both nostrils are simultaneously tested.