Table 2.
Summary of the research outcomes and quality assessments.
| References | Findings | MMAT score |
|---|---|---|
| Lopis et al. (2021) | A higher number of memories were recalled by older people, followed by PwD f and young adult. Visual stimuli evoked significantly more (p < .05) and rarer (p < .05) memories than odours, and odours stimuli produced more memories than auditory stimuli in PwD f . No significant differences were found in emotional valence and vividness memories between groups and type of sensory stimuli. PwD f (p = .01) and older people (p < .05) rated their memories significantly more emotional intense than the young adult group; no difference was found for the type of stimuli. PwD f evoked significantly more memories in the age between 0–18 (p < .05); no differences for type of stimuli and age were found | *** |
| Glachet and El Haj (2020a) | Significant increase in both groups in phenomenological characteristics of past and future (apart specificity for control group) events after odour-exposure. Significantly shorter reaction time (p = .001) for past event in PwD f after odour exposure; significantly shorter reaction time for the control group for past event (with or without odour, respectively p = .01 and p = .005) and future event (with odour) (p = .03) | *** |
| Glachet and El Haj (2020b) | Significant increase of the number of self-related statements in odour condition compared to odour-free condition in PwD f (p < .001) and control group (p < .05). Significant increase of psychological self-statements in odour condition for PwD f (p < .05). No difference in social and physical statements in both condition and groups | *** |
| Takahashi et al. (2020) | Significant decreases (p < .05) in agitation, anxiety and irritability in the exp. group at 4 and 8 weeks. No significant difference in cognitive function between the two groups. Significantly lower caregiver burden (p < .05) | * |
| Glachet et al. (2019) | Significant increase in number of childhood (p < .05), adulthood (p < .01) and recent (p < .01) memories after odour-exposure than without odour. PwD f significantly retrieved more specificity childhood (p < .01), adulthood (p < .01) and recent (p < .01) memories after odour exposure compared to odour-free condition. Regarding the temporal gradient of memories, PwD f produced more adulthood memories than childhood memories and more childhood memories than recent memories with or without odour exposure | *** |
| Glachet and El Haj (2019) | Significantly higher arousal (p < .01), subjective reliving (p < .05), specificity (p < .01) and positive (p < .01) odour-evoked autobiographical memories than for memories evoked without odour only in PwD f . Negative correlation between depression scores and emotional valence, arousal and subjective reliving in PwD f | *** |
| El Haj et al. (2018) | Memories retrieved after odour and music exposure in PwD f had higher specificity, emotional arousal, mental time travel and shorter retrieval time than in the control condition. Retrieval time was much shorter after odour exposure than music exposure | **** |
| Sulmont-Rossé et al. (2018) | A significant effect of olfactory priming in meat food intake (p = .04). A positive effect in vegetable consumption (p = .06) compared to the control condition. Significant increase in resident’s interest toward the meal in the primed lunch. This effect was no longer observed when the priming session was replicated 2 weeks later with the same priming odour and menu | **** |
| Moorman Li et al. (2017) | Non-significant reduction
(p = .06) in the frequency of
responsive behaviours pre- and
post-intervention. In the analysis of individual responsive behaviours, significant decrease only for the frequency of agitation pre- and post-intervention. Participants in the 70–85 age cohort showed a significant decrease in agitation than the 86–100 cohort post-intervention. There was no significant difference for effects of gender on any of the four behaviour responses investigated |
** |
| Takeda et al. (2017) | Total sleep time (p < .05) and sustained sleep period (p < .05) were significantly longer in the intervention period than in the control. Early morning waking in the intervention period was significantly less (p = .01) compared to that in the control. Total daytime sleep could not be adequately measured, and it was omitted from the analysis. No significant differences in other sleep measurements were observed | **** |
| Fu et al. (2013) | No significant effect was found following aromatherapy alone and aromatherapy combined with massage on participants’ responsive behaviours | **** |
| Sakamato et al. (2012) | Fewer falls in the lavender group, significant decrease in CMAI c (p = .04) from baseline to 12-month follow-up. No difference between the two groups for any of the outcomes investigated | *** |
| Jimbo et al. (2009) | A significant improvement in four GBSS-J e items (p < .05) and TDAS g (p < .05) after aromatherapy. Participants with AD a showed significant improvement in total TDAS g scores (p < .01). Blood analysis and biochemical examination showed no significant changes. Results from ZBI-J h score showed no significant changes | *** |
| Lin et al. (2007) | Significant effects were found in CCMAI b (p < .001) and CNPI d (p < .001) after odour condition. Independent sub-analysis showed no significant difference on odour condition response based on gender and subtype of dementia | *** |
| Snow et al. (2004) | No significant treatment effects were found following the two odour conditions compared the control condition | ** |
| Holmes et al. (2002) | Nine residents (60%) showed an improvement, five (33%) showed no change and one participant (7%) showed a worsening of agitated behaviour during aromatherapy compared with placebo | *** |
| Gray and Clair (2002) | No significant difference in behaviours or duration of medication administration and gender influence across the four conditions | ** |
| Smallwood et al. (2001) | No significant difference between the treatments, although consistent reduction in agitation following the aromatherapy massage. Significant time difference occurred between 3 and 4 p.m. between aromatherapy massage (p < .05) and only aromatherapy (p = .05) | *** |
| Brooker et al. (1997) | Findings varied considerably between individuals. The observations showed benefit for two people only following just aromatherapy or massage. Other two participants reported an increase of agitation following all treatment conditions apart the aromatherapy-massage for one of them | *** |
| Henry et al. (1994) | A significant increase in the total of hours slept following aromatherapy (p < .01) | * |
aAD = Alzheimer’s disease.
bCCMAI = Cohen-Mansfield Agitation Inventory Chinese version.
cCMAI = Cohen-Mansfield Agitation Inventory.
dCNPI = Neuropsychiatric Inventory Chinese version.
eGBSS-J = The Gottfries, Bråne, Steen Scale.
fPwD = People with dementia.
gTDAS = Touch-panel type Dementia Assessment Scale.
hZBI-J = Zarit Caregiver Burden Interview Japanese version. Risk of bias: (*****) low; (****) or (***) moderate; (**) or (*)high.