Light and smell stimulus protocol reduced negative frontal EEG asymmetry and improved mood

Abstract

Light and smell have both been shown to induce beneficial changes to human psychophysiology. Bright light therapy has been shown to have a positive impact on anxiety and depression and smell has also been shown to have positive effects on mood, stress, anxiety and depression. We developed a method for the delivery of integrated light and smell stimulation to try to optimise positive psychophysiological benefit. We tested its effectiveness on a physiological measure, EEG frontal alpha asymmetry (FA) and a psychological paradigm, the POMS test, both of which have been used as a measure of emotional state and mood. Light, pleasant smell, combined light+smell and a no stimulus control were delivered for 90s while the frontal alpha asymmetry (FA) was monitored. Smell and light+smell caused significant reductions in negative FA during stimulation. Exposure to a longer 15 min nonadaptive light+smell stimulus protocol reduced negative FA and decreased negative affect (POMS). The effects were greater in the negative FA group. Both the physiological (EEG) and psychometric (POMS) data indicate that integrated light and smell stimulation can reduce negative affect and reduce a marker for anxiety/ depression. This light+smell sensory stimulation protocol could offer a safe treatment for depression/anxiety.

Frontal EEG Asymmetry of Mood: A Mini-Review

“…From the studies reviewed on the EEG correlates of mood it appears that, regardless the research line considered, there are contrasting results that cannot be unequivocally interpreted according to one frontal asymmetry model rather than to another. The motivational approach/withdrawal and valence/arousal models appear to be the most supported ones (Tucker et al, 1981 ; Schaffer et al, 1983 ; Henriques and Davidson, 1990 , 1991 ; Tomarken et al, 1990 , 1992a , b ; Allen et al, 1993 ; Wheeler et al, 1993 ; Gotlib et al, 1998 —Study 1; Mathersul et al, 2008 ; Rodriguez et al, 2015 ; Warden-Smith et al, 2017 ). However, it is difficult to disentangle the contributions of specific studies to the two models given that the models overlap in terms of empirical predictions (Spielberg et al, 2008 ).…”

“…Secondly, it also appears that sample should be better composed. Indeed, different studies reviewed used only females (e.g., Tomarken et al, 1990 ; Wheeler et al, 1993 ; Gotlib et al, 1998 ; Reid et al, 1998 ; Gale et al, 2001 ), or much more females than males (e.g., Dennis and Solomon, 2010 ; Mikolajczak et al, 2010 ); one study enrolled only males (Jacobs and Snyder, 1996 ), and one study reported no information about gender (Warden-Smith et al, 2017 ). Only recently studies have increased the interest in gender-related brain mechanisms and cerebral lateralization subserving emotional processing (e.g., Gasbarri et al, 2006 , 2007 ; Arnone et al, 2011 ).…”

“…Kop et al ( 2011 ) also found increased right frontal activation during induced positive mood induction, which was associated with a decrease in low frequency/high frequency ratio of the heart rate variability. Interestingly, Warden-Smith et al ( 2017 ) showed that a positive mood induction yielded a decrease of right frontal asymmetry and an increase of left frontal asymmetry in negative alpha fontal group, as if a change in alphawave activity in the direction of positive affect occurred in people susceptible to negative affect. Yet, Gotlib et al ( 1998 ) found in the study 2 that frontal EEG asymmetry was unrelated to mood reactivity and cognitive functioning.…”

Effects on Mood and EEG States After Meditation in Augmented Reality With and Without Adjunctive Neurofeedback

“…It has been suggested that trait levels of depressed affects are associated with suppressed left frontal activity (Davidson, 1992), and that high frequency activity in the left frontal cortex are linked with positive mood states and approach behaviors whereas right lateralized frontal activity is linked with negative mood states and withdrawal behaviors (Sutton and Davidson, 1997). Multiple studies examining EEG frontal asymmetries and the induction of mood states have demonstrated greater right activation with induced positive mood and greater left activation with negative moods (Kop et al, 2011;Warden-Smith et al, 2017). Other studies have found no connection between frontal EEG asymmetry and mood reactivity (Gotlib et al, 1998;Dennis and Solomon, 2010), potentially because these patterns are moderated by individual factors such as personality traits (Gale et al, 2001) and individual differences in functional neural lateralization (Lezak et al, 2012).…”

Diurnal effects of dynamic lighting on alertness, cognition, and mood of mentally fatigued individuals in a daylight deprived environment

“…Technol. 2024; 56: [136][137][138][139][140][141][142][143][144][145][146][147][148][149][150][151][152][153][154][155] Moreover, further research should also combine dynamic light with other sensory stimuli (e.g., light-smell combinations 69,70 ) to explore fatigue intervention measures based on multisensory stimulation in a daylight-deprived environment.…”