Why This Matters

Caring for someone living with Alzheimer’s disease or other dementias often leads families and professionals to explore therapies that might support cognition, mood, or quality of life for their loved ones. Among such options, aromatherapy is frequently discussed in caregiver communities and complementary care settings. (Article continued below video…)

Although not a dementia-specific study, research on how olfactory (smell) stimulation affects thinking and emotion can offer insight into mechanisms that might be relevant for people with cognitive impairment and the environments caregivers create to support them.

What the Study Tested

Researchers randomly assigned 144 healthy adult volunteers into three groups. Each group performed a standardized computerized cognitive test battery in a cubicle scented with:

• rosemary essential oil
• lavender essential oil
• no odor (control)

Participants were unaware of the study’s true aim until after testing to reduce expectancy effects. Mood was assessed before and after testing using visual analog scales.

Key Findings for Cognitive Performance

• Lavender aroma was associated with poorer performance on working memory tasks and slower reaction times on tests involving memory and attention, compared with the control condition.
• Rosemary aroma produced better scores on measures of memory quality and “secondary memory” (recall of previously presented material) than the control group, but it also slowed speed of memory retrieval.
• Mood ratings suggested people exposed to rosemary stayed more alert after testing, compared with participants in the control or lavender groups.

In short, different aromas appeared to produce distinct effects on cognition and mood in healthy adults. Rosemary showed some memory benefits but at a cost in processing speed, while lavender tended to impair working memory and attention in these conditions.

What This Means for Alzheimer’s and Dementia Care

This study does not directly involve people living with Alzheimer’s disease. Nevertheless, the findings contribute to a broader evidence base suggesting that olfactory stimulation interacts with cognitive processes. People with dementia often experience altered responses to sensory input — including smell — which can influence behavior, mood, and engagement.

Caregivers and professionals should interpret these results with care:

1. Not all scents are equal. Different odors may have divergent effects on cognition and alertness. What enhances one cognitive domain might impair another.
2. Individual responses vary. Sensory perception changes with age and disease; what is calming for one person may be confusing or aversive for another.
3. Clinical context matters. Aromatherapy research in dementia populations has shown mixed but sometimes positive effects on agitation and behavior, but mechanisms and optimal protocols are still under study.

Practical Takeaways for Caregivers

• Before introducing any scent-based intervention, observe the person’s reactions in small, controlled doses rather than assuming universal benefit.
• Use scents that the individual personally associates with comfort or positive experience rather than relying solely on purported cognitive effects.
• Aromatherapy should be complementary to — not a replacement for — evidence-based dementia care practices such as social engagement, structured activities, and environmental design.

What Needs More Research

• Studies involving people living with Alzheimer’s disease and other dementias, rather than healthy volunteers.
• Standardized protocols for type, duration, and dosing of aroma exposure.
• Investigations into how olfactory stimulation interacts with behavioral symptoms, sleep, and emotional well-being in dementia care settings.