Reduced sense of smell

A reduced sense of smell (also known as ‘hyposmia’) is now recognised as a very early feature that can be detected in some (not all) untreated, newly diagnosed people with Parkinson’s disease (PD). It is caused by damage to the nerve cells in the part of the brain that controls the sense of smell.

Although this symptom is not physically disabling, it can impair the enjoyment of food (including reduced appreciation of the taste of food) as part of daily life. In the future, prompt recognition of this symptom may be important in producing an early diagnosis of PD.