Smell Loss Signals Early Brain Disease, Research Shows

Studies and experts have identified the loss of smell as an early indicator of Alzheimer's and Parkinson's, with smell training showing potential cognitive benefits.

• Experts said loss of smell may appear up to 10 years before other symptoms of Alzheimer's or Parkinson's.
• A 2021 study found that 90% of early Parkinson's patients and 85% of early Alzheimer's patients suffer from smell disorders.
• Researchers said smell training, which involves repeatedly sniffing different scents, may restore smell and boost cognitive function via neuroplasticity.
• A long-term study of 408 adults found the sense of smell was a better predictor of cognitive decline than hearing or sight.