Loss of smell linked to neurological conditions

Losing one's sense of smell is one of the first signs of onset for a number of neurodegenerative conditions including Parkinson's and Alzheimer's, and according to new research from Perelman School of Medicine at the University of Pennsylvania, one more disease is being added to the list.

The research is bolstered by further evidence from the University of Montreal and the U.S. Department of Veteran Affairs, who published studies this year linking olfactory loss to Parkinson's and Alzheimer's.

Study results
Researchers from the University of Pennsylvania went one step beyond previous studies, linking loss of smell to myasthenia gravis (MG), an autoimmune neuromuscular disease that affects patients' muscles and energy levels. According to senior author Richard Doty, PhD, this first-time correlation could lead to a stronger understanding of the brain's involvement in disorders of the peripheral nervous system.

Those with myasthenia gravis are at increased risk of depression, according to the Myasthenia Gravis Foundation of Illinois. Patients may buy Effexor or buy Paxil to treat depression or anxiety conditions, or may seek alternate or combined treatments.

MG results from poor communication between nerves and muscles, and was previously thought to ignore the central nervous system altogether. Part of this belief has stemmed from mixed studies, with just as many participants showing memory reduction as showing no change. Conditions relating to the central nervous system have continually been reported relating to MG, however, including sensory problems with hearing and sight. Electroencephalograms have additionally revealed abnormalities and MG-related antibodies in cerebrospinal fluid in MG patients.

Research methods
The Pennsylvania study included 27 individuals with MG, 27 healthy individuals and 11 patients with polymyositis, an inflammatory disease of the autoimmune system that causes pain and tenderness in the patient's muscles.

Study participants were given the UPSIT - the University of Pennsylvania Smell Identification Test. The test paired images and smells to determine whether participants could inhale and process smells appropriately. MG patients scored lower than those in the other control groups, with only 15 percent aware at the time that a problem with their olfactory sense existed.

The research suggests that further data should be collected to determine how MG interacts with the brain, particularly since most symptoms are muscular in nature. The research could also lead doctors to view new treatment options for their patients with MG.