Early symptoms of Alzheimer’s disease are often subtle and first appear as minor memory lapses—forgetting names, repeating questions, or misplacing objects—which are easily mistaken for normal aging. However, research shows the disease begins affecting the brain years before noticeable memory loss, prompting scientists to seek earlier warning signs.

One surprising early indicator is a decline in the sense of smell. The brain regions involved in scent recognition overlap with those responsible for memory and learning, making olfactory changes an early marker of neurological alterations. Difficulty identifying familiar odors—soap, flowers, smoke, or food—can occur well before cognitive impairment is obvious. Long-term studies confirm that individuals who struggle with odor identification are at significantly higher risk of future cognitive decline.

When smell tests are combined with brief memory assessments, predictive accuracy improves further, sometimes approaching that of advanced imaging or lab tests. These tests are noninvasive, inexpensive, quick, and practical for routine medical visits, making them ideal for early screening.

Early recognition allows healthcare providers and families to take proactive steps, including monitoring, cognitive exercises, physical activity, and social engagement, which may help slow disease progression and maintain quality of life. Paying attention to small sensory changes, such as smell loss, can serve as an important cue for early intervention and long-term cognitive health.