While there can be several different reasons for changes in the ability to properly smell and taste, if there is a sudden change in a person’s ability to properly smell or taste following brain injury, then the doctor should look to the brain injury as the cause of the change in smell or taste.Unfortunately, due to the ability of the brain injury survivor to have full insight into all of their symptoms, it is common that they begin changing their eating patterns, typically over-seasoning their food, before they even realize they have a diminished sense of smell or taste.
There are several different medical diagnoses concerning changes in the ability to smell and taste, including the following:
- Anosmia – a complete loss of sense of smell
- Hyposmia – a diminished sense of smell
- Parosmia – a change or alteration in the sense of smell
- Ageusia – a complete loss of sense of taste
- Hypogeusia – a partial loss of sense of taste
- Dysgeusia – a change or alteration in the sense of taste
The ability to taste certain types of food is closely linked to the ability to smell, so often the change in sense of smell results in a change in the ability to fully taste everything.
Importantly, it is not the injury to the brain itself that causes the change in the ability to smell or taste, instead it is typically separate damage to the Olfactory Bulb that results in the change in smell or taste. The Olfactory Nerves carry information from the nose to the brain. Unfortunately, it must travel into the skull in an area with rough, sharp ridges called the Cribriform Plate, which makes the Olfactory Nerves very susceptible to trauma. (See Diagram to the Right). In an accident, if there is enough force to cause a brain injury, then there certainly will also be enough force to cause damage to the Olfactory Nerves and/or Olfactory Bulb.
Changes in the sense of smell are usually detected through the administration of a Smell Test. While there are a variety of different Smell Tests, the most common is the University of Pennsylvania Smell Identification Test or UPSIT, which was invented by Richard Doty, PhD, a pioneering researcher in the loss of sense of smell. The UPSIT is essentially a scratch and smell test of 40 items. The test can be self-administered, it can detect if someone is not being accurate regarding their loss of smell and it is also normed for age, gender, smoking habits, and a wide variety of olfactory disorders.
Unfortunately, in my experience representing brain injury survivors, I have found that doctors and neuropsychologists rarely even ask their patients if they have noticed a change in their ability to smell or taste, let alone administer a valid smell or taste test. TBI survivors that have noticed changes in their sense of smell or taste must bring it to their doctors attention. They should be referred to an ENT for administration of a valid Smell Test and to explore potential treatment options, which can include zinc supplements, medications or possibly even surgery. Unfortunately, post-traumatic Anosmia and/or Ageusia is usually not curable.