Forrester LT, Maayan N, Orrell M, Spector AE, Buchan LD, Soares-Weiser K. Aromatherapy for dementia. Cochrane Database Syst Rev. 2014;2:CD003150. doi: 10.1002/14651858.CD003150.pub2.
Olfaction can trigger memories. People with dementia have a greater prevalence of anosmia (the inability to perceive odors). Aromatherapy is used to treat behavioral and psychological symptoms in dementia (i.e., reduce disturbed behavior, promote sleep, and stimulate motivation). The purpose of this review was to assess the efficacy of aromatherapy for people with dementia. This Cochrane review is a 2014 update to the 2008 Cochrane review.
ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group Specialized Register, was searched on November 26, 2012 and January 20, 2014. ALOIS contains data from numerous electronic databases, clinical trials registries, and grey literature sources. The search terms used were aromatherapy, lemon, lavender, rose, aroma, alternative therapies, complementary therapies, and essential oils. The inclusion criteria were as follows: patients with a diagnosis of dementia of any type and severity, based on diagnostic criteria such as the International Classification of Diseases-10 (ICD-10) and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) or well-validated assessment scales for cognitive function, such as the Mini-Mental State Examination (MMSE) and the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog); all doses, frequencies, and fragrances of aromatherapy; and randomized controlled trials (RCTs). The quality of studies was assessed using the Cochrane Risk of Bias Tool.
Of the 38 full-text articles assessed for eligibility, seven studies were included in the qualitative analysis. One study was conducted in Hong Kong, two were conducted in Australia, and four were conducted in the United Kingdom. Cumulatively, these studies involved 428 patients with either dementia with agitation or Alzheimer's disease with agitation. Patients were a mean of 67-85 years old, and approximately 60% were women. The treatments ranged from three to 12 weeks in duration.
The treatments evaluated were as follows: (1) 10% lemon balm (melissa; Melissa officinalis) and base lotion applied topically to the arms and face two times/day for one to two minutes vs. sunflower (Helianthus annuus) oil control; (2) lemon balm oil two times/day massaged into the hands and upper arms for one to two minutes vs. active medication (donepezil) control and sunflower oil control; (3) < 2% lemon balm oil rubbed into the forearm for one minute two times/day vs. 1% geranium (Pelargonium spp.) and 0.5% lemon (Citrus × limon) oil control; (4) 3% lavender (Lavandula angustifolia) mist – three sprays applied two times/day to the upper chest within a 30 cm distance (one group with and another group without hand massage) vs. water mist control; (5) lavender oil vs. sunflower oil control (two drops of oil on two pieces of cosmetic cotton that was placed into an aroma diffuser on either side of the patient's pillow for at least one hour during sleep); (6) 30% lavender in jojoba (Simmondsia chinensis) oil vs. jojoba oil control (oils massaged into both forearms for one minute each; 1 mL per arm giving a total of 2 mL per session); and (7) lavender applied topically with massage vs. lavender in a diffuser accompanied by conversation control and massage-only control.
The overall quality of evidence was very low. The risk of bias was low overall, except for selective reporting (five of seven studies had a high risk of bias). Of the five studies that assessed agitation, two found aromatherapy decreased agitation and three found no significant effect. Three studies evaluated behavioral symptoms; one found aromatherapy was beneficial and two found no treatment effect.
Due to the methodological heterogeneity of the trials, only two studies could be combined into a meta-analysis. One study (n = 71) showed that the aromatherapy (10% lemon balm; treatment #1 above) was significantly better than control on measures of agitation and behavioral symptoms. In contrast, the second study (n = 63; treatment #2 above) found that treatment had no significant effect on agitation, behavioral symptoms, activities of daily living, or quality of life.
Two studies showed no significant differences in adverse effects compared to placebo.
The results of numerous case studies and open trials which largely reported positive results were also summarized. The authors conclude that while there is plenty of non-randomised evidence of both benefit and harm, the randomised trials included in this review show equivocal evidence. "More well-designed, large-scale RCTs that fully report the data are needed before conclusions can be drawn as to its effectiveness." They also point out that there are numerous methodological issues which need to be addressed in future studies.—Heather S. Oliff, PhD