What the Nose Knows - Avery Gilbert [24]
Head injury is the second leading cause of smell loss. A blow to the head can sever some of the olfactory nerve fibers that travel to the brain through tiny holes in the base of the skull, at a location between the ears and behind the eyes. There’s an old (and possibly true) story about a waiter carrying a tray of food at head height. As he exits the kitchen, the swinging door slams the tray into his forehead. Being a professional, he maintains his balance and proceeds into the dining room. As he serves the dishes, he realizes he can’t smell a single one. The speed with which the waiter discovers his loss might be unusual—most people don’t notice for days or weeks—but the mildness of the damaging blow is not. It takes very little force to cause smell loss. I cringe when I see kids heading the ball in a soccer game. I wouldn’t bet on them becoming chefs or perfumers.
With the exception of a stuffy nose, smell loss is a long-term condition. Smell may return after a flu or sinus infection, as the damaged sensory cells are gradually replaced by new ones, but recovery can take months and your abilities may never return to their original levels. The probability of recovery declines with age. In cases of head trauma, the prospects are bleak; the severed nerve fibers rarely reconnect. Consider the results of a typical study: a year after their initial visit to the doctor, 32 percent of postinfection patients showed improvement, compared with only 10 percent of the post-injury group. The realization that millions of Americans suffer from smell loss spurred the National Institutes of Health to underwrite basic research into odor perception. The ultimate goal of this work was to find ways to cure smell loss. Yet, despite decades of substantial funding, effective medical treatment remains elusive.
Sudden smell loss is psychologically devastating. By far the biggest impact is on eating: anosmia steals the pleasures of the table. Without its aroma, food in the mouth becomes a bland, chewy mass, and drinks become equally flavorless. Faced with dull food, some people lose appetite, eat less, and lose weight; others eat to feel full and end up gaining weight. Smell loss can alter mood—patients often show symptoms of depression, and psychological well-being, friendship, emotional stability, and leisure activities all take a hit. Some people find that their sex life suffers. In the wake of smell loss comes the anxiety of constant vigilance. Anosmics worry about gas leaks, undetected fire, spoiled food, and lapses in personal hygiene. They adopt coping strategies such as frequent bathing and laundering. Anosmics report smell-related hazardous events—burning a pot or eating spoiled food—more often than normal smellers, but there is little data to suggest a higher rate of actual injury.
In rare instances, people are born without a sense of smell. As it’s hard to miss what you’ve never known, people who are anosmic from birth tend to regard their condition with bemusement. A few even manage to find a silver lining. The ex-boyfriend of a young English anosmic told her, “You were the best girlfriend in the world. You let me bring curry home from the pub every night, and I could fart as much as I liked.” One newspaper reporter who is smell-blind from birth regularly covers smelly stories for a major U.S. daily. This is either a heartwarming story of a disability overcome, or journalistic malpractice of the first order. Perhaps, in a zany way, it is both.
Somewhere off the main continuum of normal to partial to complete smell loss lie the bizarre pathologies of odor perception. A person with phantosmia,