The therapeutic potential of phytoncide fragrances may be optimal for patients with mild cognitive impairment (MCI) that display complex symptomatology. This study aimed to explore the clinical value of phytoncide by evaluating its electrophysiological effects in patients with MCI.
Materials and Methods:
This was a double-blind, randomized controlled trial. A total of 24 community-dwelling patients were randomly assigned to either a phytoncide or no-odor group. Participants wore a dental mask, for 30 min at rest that had either the fragrance stimulus or water added to it. The quantitative electroencephalography (EEG) during the resting state was recorded before and after a single intervention.
Results:
There were significant interaction effects in absolute EEG-power values in the occipital (F = 6.52, p = 0.018) and parietal (F = 5.41, p = 0.030) left hemisphere at β frequency. Phytoncide odor significantly decreased low and high β activity in the occipital (corrected p = 0.009) and parietal (corrected p = 0.047) left hemisphere, respectively. In source localization, phytoncide odor significantly decreased deep source activation in the left inferior and middle frontal gyri at β 2 frequency band compared with the no-odor group (threshold = 4.25, p < 0.05).
Conclusions:
Reductions in β, indicative of anxiety, depression, and stress, suggest relief from emotion-related symptoms that are common in patients with MCI.
Trial Registration:
Clinical Trials Registry Korea (registration: KCT0007317).
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References
1.
ThangaleelaS, SivamaruthiBS, KesikaP, et al.Essential oils, phytoncides, aromachology, and aromatherapy—A review. Appl Sci, 2022; 12(9):4495; 10.3390/app12094495
2.
WooJ, LeeCJ. Sleep-enhancing effects of phytoncide via behavioral, electrophysiological, and molecular modeling approaches. Exper Neurobiol, 2020; 29(2):120; doi: 10.5607/en20013
3.
NomuraM. Phytoncide–its properties and applications in practical use. In: Gas Biology Research in Clinical Practice. Karger Publishers;, 2011; pp. 133–143; doi: 10.1159/000321956
4.
TsunetsuguY, ParkB-J, MiyazakiY. Trends in research related to “Shinrin-yoku”(taking in the forest atmosphere or forest bathing) in Japan. Environ Health Prevent Med, 2010; 15(1):27–37; doi: 10.1007/s12199-009-0091-z
5.
HeoS-J, ParkS-K, JeeY-S. Effects of phytoncide on immune cells and psychological stress of gynecological cancer survivors: Randomized controlled trials. J Exer Rehab, 2023; 19(3):170; doi: 10.12965/jer.2346150.075
6.
ButjeA, RepedeE, ShattellMM. Healing scents: An overview of clinical aromatherapy for emotional distress. J Psychosoc Nurs Ment Health Serv, 2008; 46(10):46–52; doi: 10.3928/02793695-20081001-12
7.
HorowitzS. Aromatherapy: Current and emerging applications. Alt Complement Ther, 2011; 17(1):26–31; doi: 10.1089/act.2011.17103
KimC-G, ChoM-K, KimJ-I. Effects of phytoncide aromatherapy on stress, symptoms of stress and heart rate variability among nursing students. J Kor Biol Nurs Sci, 2012; 14(4):249–257; doi: 10.7586/jkbns.2012.14.4.249
10.
ParkB-J, TsunetsuguY, KasetaniT, et al.Physiological effects of forest recreation in a young conifer forest in Hinokage Town, Japan. Silva Fenn, 2009; 43(2):291–301. Available from: www.metla.fi/silvafennica/full/sf43/sf432291.pdf
11.
AntonelliM, DonelliD, BarbieriG, et al.Forest volatile organic compounds and their effects on human health: A state-of-the-art review. Int J Environ Res Pub Health, 2020; 17(18):6506; doi: 10.3390/ijerph17186506
12.
WinbladB, PalmerK, KivipeltoM, et al.Mild cognitive impairment–beyond controversies, towards a consensus: Report of the International Working Group on Mild Cognitive Impairment. J Int Med, 2004; 256(3):240–246; doi: 10.1111/j.1365-2796.2004.01380.x
13.
LeeC-Y, ChengS-J, LinH-C, et al.Quality of life in patients with Dementia with Lewy Bodies. Behav Neurol, 2018;2018; doi: 10.1155/2018/8320901
14.
XuY, QiuZ, ZhuJ, et al.The modulation effect of non-invasive brain stimulation on cognitive function in patients with mild cognitive impairment: A systematic review and meta-analysis of randomized controlled trials. BMC Neurosci, 2019; 20(1):1–11; doi: 10.1186/s12868-018-0484-2
15.
PanzaF, FrisardiV, CapursoC, et al.Late-life depression, mild cognitive impairment, and dementia: Possible continuum?. Am J Geriatr Psychiatr, 2010; 18(2):98–116; doi: 10.1097/JGP.0b013e3181b0fa13
16.
MouraoRJ, MansurG, Malloy-DinizLF, et al.Depressive symptoms increase the risk of progression to dementia in subjects with mild cognitive impairment: Systematic review and meta-analysis. Int J Geriatr Psychiatr, 2016; 31(8):905–911; doi: 10.1002/gps.4406
17.
RichardE, ReitzC, HonigLH, et al.Late-life depression, mild cognitive impairment, and dementia. JAMA Neurol, 2013; 70(3):383–389; doi: 10.1001/jamaneurol.2013.603
18.
AngelucciF, SilvaV, Dal PizzolC, et al.Physiological effect of olfactory stimuli inhalation in humans: An overview. Int J Cosmet Sci, 2014; 36(2):117–123; doi: 10.1111/ics.12096
19.
SowndhararajanK, KimS. Influence of fragrances on human psychophysiological activity: With special reference to human electroencephalographic response. Sci Pharmaceut, 2016; 84(4):724–752; doi: 10.3390/scipharm84040724
20.
KimM, SowndhararajanK, ChoiHJ, et al.Olfactory stimulation effect of aldehydes, nonanal, and decanal on the human electroencephalographic activity, according to nostril variation. Biomed, 2019; 7(3):57; doi: 10.3390/biomedicines7030057
21.
SowndhararajanK, ChoH, YuB, et al.Effect of inhalation of essential oil from Inula helenium L. root on electroencephalographic (EEG) activity of the human brain. Euro J Integ Med, 2016; 8(4):453–457; doi: 10.1016/j.eujim.2016.01.005
22.
SellCS.The Chemistry of Fragrances: From Perfumer to Consumer. Royal Society of Chemistry; 2006.
23.
BoutronI, AltmanDG, MoherD, et al.CONSORT statement for randomized trials of nonpharmacologic treatments: A 2017 update and a CONSORT extension for nonpharmacologic trial abstracts. Ann Int Med, 2017; 167(1):40–47; doi: 10.7326/M17-0046
24.
BoutronI, MoherD, AltmanDG, et al.Extending the CONSORT statement to randomized trials of nonpharmacologic treatment: Explanation and elaboration. Ann Int Med, 2008; 148(4):295–309; doi: 10.7326/0003-4819-148-4-200802190-00008
25.
American Psychiatric AssociationA, AssociationAP. Diagnostic and Statistical Manual of Mental Disorders: DSM-5. American Psychiatric Association: Washington, DC, USA; 2013.
26.
PetersenRC. Mild cognitive impairment as a diagnostic entity. J Int Med, 2004; 256(3):183–194; doi: 10.1111/j.1365-2796.2004.01388.x
CobenR, ClarkeAR, HudspethW, et al.EEG power and coherence in autistic spectrum disorder. Clin Neurophysiol, 2008; 119(5):1002–1009; doi: 10.1016/j.clinph.2008.01.013
30.
HaendelAD, BarringtonA, MagnusB, et al.Changes in electroencephalogram coherence in adolescents with autism spectrum disorder after a social skills intervention. Autism Res, 2021; 14(4):787–803; doi: 10.1002/aur.2459
Pascual-MarquiRD, LehmannD, FaberP, et al.The resting microstate networks (RMN): Cortical distributions, dynamics, and frequency specific information flow. arXiv preprint arXiv:14111949, 2014; doi: 10.48550/arXiv.1411.1949
33.
CohenJ. Eta-squared and partial eta-squared in fixed factor ANOVA designs. Edu Psychol Measure, 1973; 33(1):107–112; doi: 10.1177/001316447303300111
34.
SeoM, SowndhararajanK, KimS. Influence of binasal and uninasal inhalations of essential oil of Abies koreana twigs on electroencephalographic activity of human. Behav Neurol, 2016; doi: 10.1155/2016/9250935
35.
KimM, SowndhararajanK, KimT, et al.Gender differences in electroencephalographic activity in response to the earthy odorants geosmin and 2-methylisoborneol. App Sci, 2017; 7(9):876; doi: 10.3390/app7090876
36.
SchmidtR, RuizMH, KilavikBE, et al.Beta oscillations in working memory, executive control of movement and thought, and sensorimotor function. J Neurosci, 2019; 39(42):8231–8238; doi: 10.1523/JNEUROSCI.1163-19.2019
37.
DíazH, CidFM, OtárolaJ, et al.EEG Beta band frequency domain evaluation for assessing stress and anxiety in resting, eyes closed, basal conditions. Procedia Comput Sci, 2019; 162:974–981; doi: 10.1016/j.procs.2019.12.075
38.
EngelAK, FriesP. Beta-band oscillations—Signalling the status quo?. Curr Opin Neurobiol, 2010; 20(2):156–165; doi: 10.1016/j.conb.2010.02.015
39.
BruderGE, FongR, TenkeCE, et al.Regional brain asymmetries in major depression with or without an anxiety disorder: A quantitative electroencephalographic study. Biol Psychiatr, 1997; 41(9):939–948; doi: 10.1016/S0006-3223(96)00260-0
40.
WangS-Y, LinI-M, FanS-Y, et al.The effects of alpha asymmetry and high-beta down-training neurofeedback for patients with the major depressive disorder and anxiety symptoms. J Affect Dis, 2019; 257:287–296; doi: 10.1016/j.jad.2019.07.026
41.
AcunaBD, EliassenJC, DonoghueJP, et al.Frontal and parietal lobe activation during transitive inference in humans. Cereb Cort, 2002; 12(12):1312–1321; doi: 10.1093/cercor/12.12.1312
42.
HerzRS, McCallC, CahillL. Hemispheric lateralization in the processing of odor pleasantness versus odor names. Chem Sense, 1999; 24(6):691–695; doi: 10.1093/chemse/24.6.691
43.
GudziolV, HummelC, NegoiasS, et al.Lateralized differences in olfactory function. Laryngoscope, 2007; 117(5):808–811; doi: 10.1097/MLG.0b013e3180330092
44.
GudziolV, PaechI, HummelT. Unilateral reduced sense of smell is an early indicator for global olfactory loss. J Neurol, 2010; 257(6):959–963; doi:10.1007/s00415-009-5445-3
45.
AdlerG, BramesfeldA, JajcevicA. Mild cognitive impairment in old-age depression is associated with increased EEG slow-wave power. Neuropsychobiol, 1999; 40(4):218–222; doi: 10.1159/000026623
46.
DierksT, FrölichL, IhlR, et al.Correlation between cognitive brain function and electrical brain activity in dementia of Alzheimer type. J Neur Transm/Gen Section JNT, 1995; 99(1):55–62; doi: 10.1007/BF01271469
47.
KoberdaJL, MosesA, KoberdaP, et al.Clinical advantages of quantitative electroencephalogram (QEEG)–electrical neuroimaging application in general neurology practice. Clin EEG Neurosci, 2013; 44(4):273–285; doi: 10.1177/1550059412475291
48.
ChiaramontiR, MuscasG, PaganiniM, et al.Correlations of topographical EEG features with clinical severity in mild and moderate dementia of Alzheimer type. Neuropsychobiol, 1997; 36(3):153–158; doi: 10.1159/000119375
49.
IhlR, DierksT, MartinE-M, et al.Topography of the maximum of the amplitude of EEG frequency bands in dementia of the Alzheimer type. Biol Psychiatr, 1996; 39(5):319–325; doi: 10.1016/0006-3223(95)00174-3
50.
LinF, RenP, LoRY, et al.Insula and inferior frontal gyrus' activities protect memory performance against Alzheimer's disease pathology in old age. J Alz Dis, 2017; 55(2):669–678; doi: 10.3233/JAD-160715
51.
LiM, ZhengG, ZhengY, et al.Alterations in resting-state functional connectivity of the default mode network in amnestic mild cognitive impairment: An fMRI study. BMC Med Imag, 2017; 17(1):1–8; doi: 10.1186/s12880-017-0221-9
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