Shake, Rattle and Roll: My Dog’s Nose Knows

I wish I had my dog’s nose, even for 10 minutes.

When we go for a walk, Oreo, our beloved English Springer Spaniel, a hunting and bird dog, experiences the world nose-first. She is likely to smell chocolate leftover from Halloween buried in the autumn leaves. Walk a little further and she sniffs urine on the tree where a male dog marked his territory. Then Oreo whiffs the sweet and sour scent of crabapples along our path. Oreo really gets excited when she picks up the musty smell emanating from the sewer where the den of raccoons spent the night.

I, on the other hand, smell nothing.

The loss of smell (hyposmia) is a hallmark symptom of many neurological diseases, including Parkinson’s Disease (PD). Smell loss is a more common symptom of PD than tremor. Unfortunately, I have both symptoms. One of the most common sensory problems of PD patients is the inability to detect and discriminate odors.

I can’t remember when my sniffer became “not up to snuff.” It most likely began when my PD journey started more than 11 years ago.

Nicolaas Bohnen, MD, Associate Professor of Radiology and Neurology at the University of Michigan in Ann Arbor, and his team sought to determine whether a selective pattern of smell deficit might exist in patients with PD. They used the University of Pennsylvania Smell Identification Test (UPSIT), a self-administered battery of 40 scratch-and-sniff odors ranging from turpentine to roses to pizza.

The investigators found that patients with PD did worse compared with controls on identifying eight odors, listed in order of decreasing odor identification: licorice, coconut, banana, dill pickle, paint thinner, turpentine, cherry, and soap. PD patients were better able to distinguish only one smell: lemon.

The impairment of the sense of smell is so common in Parkinson's patients it is has been suggested as a possible diagnostic tool. Dr. Bohnen also noted that smell testing may be more reliable than motor testing, especially for patients in the earliest stages of PD. He also suggests that a combination of smell and cognitive testing is better at predicting a dopamine deficit than are motor tests.

While I remain envious of my dog’s keen ability to smell, with PD I need to keep myself safe without a sense of smell. I hope that Oreo’s nose will alert me if she smells something dangerous because her nose knows.