Parkinson Foundation of Harris County

Parkinson’s Disease and the “Senses”

Aliya I. Sarwar M.D.

Parkinson’s disease (PD) is viewed as a disease of the motor system; however, it is important to know that a variety of sensory symptoms are a part and parcel of this disease.

The best recognized is loss or reduction in the sense of smell. Research shows that reduction in the sense of smell may predate development of Parkinson’s disease by several years, hence could be an “early marker” of the disease. Relatives of PD patients with impaired sense of smell have a 10% increased risk for developing PD in the subsequent 2 years than those with normal sense of smell. In a study involving 62 pairs of twins, in which one from each pair suffered from PD, the one inflicted with the disease had reduced ability to identify various smells than the twin without the disease.

Reduced sense of smell or “olfactory dysfunction” is believed to be due to cell loss in amygdala and/or decreased dopaminergic neurons in the olfactory bulb (areas involved in processing of the sense of smell). There is no treatment for this problem. Loss or reduction of the sense of smell generally also affects a person’s sense of taste and may contribute to reduced appetite and weight loss. It may also be a safety risk as patients may not be able to detect a gas leak, burning food or fire within their surroundings. General care and safety planning for PD patients should take this limitation in consideration.

Other sensory symptoms in PD include shoulder pain (and stiffness) generally involving the most affected side, and ill defined pain in the mouth, groin or genital areas. These may or may not respond to anti-PD medication. A variety of pain medications in conjunction with physical therapy (where feasible) can be tried for treatment.

Dated: 04-19-10