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Dysfunctional Incidental Olfaction in Mild Cognitive Impairment (MCI): An Electroencephalography (EEG) Study.

Walla P, Duregger C, Deecke L, Dal-Bianco P - Brain Sci (2011)

Bottom Line: On the other hand, the patient group did not show any such difference activities.None of these were found in MCI patients, although it has to be emphasised that our sample size was rather small.We confirm previous findings about olfactory related dysfunction in patients with MCI and conclude from our findings that even subliminal odour-related information processing is impaired.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, Faculty of Science and Information Technology, University of Newcastle, Callaghan 2308 NSW, Australia. peter.walla@newcastle.edu.au.

ABSTRACT
Our study provides evidence that Mild Cognitive Impairment (MCI) is associated with olfactory dysfunction on both conscious and non-conscious levels. MCI patients and age-matched controls underwent a face processing task during which sympathy decisions had to be made via button presses. Incidentally, some of the faces were associated with a simultaneously presented odour. Although attention was paid to faces, brain activities were analysed with respect to odour versus no-odour conditions. Behavioural differences were found related to overall face recognition performance, but these were not statistically significant. However, odour-related neurophysiology differed between both groups. Normal controls demonstrated brain activity differences between odour and no-odour conditions that resemble difference activity patterns in healthy young participants as described in a previous magnetoencephalography (MEG) study [1]. They showed odour-related activity patterns between about 160 ms and 320 ms after stimulus onset and between about 640 ms and 720 ms. On the other hand, the patient group did not show any such difference activities. Based on previous research we interpret the early odour-related brain activity pattern in controls as being associated with subliminal olfaction and the later activity pattern with conscious olfaction. None of these were found in MCI patients, although it has to be emphasised that our sample size was rather small. We confirm previous findings about olfactory related dysfunction in patients with MCI and conclude from our findings that even subliminal odour-related information processing is impaired.

No MeSH data available.


Related in: MedlinePlus

LORETA solutions for the early odour-related effect in controls. Maximum brain activity difference between odour versus no-odour can be seen at the left fronto-temporal area.
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f3-brainsci-01-00003: LORETA solutions for the early odour-related effect in controls. Maximum brain activity difference between odour versus no-odour can be seen at the left fronto-temporal area.

Mentions: We tested the hypothesis that MCI patients demonstrate different brain activity patterns related to incidental olfactory information processing compared to age-matched controls due to their known olfactory impairment. This can be confirmed. In comparison to previous findings [1] the present study too revealed significant brain activity differences between the conditions faces without odour and faces with odour in healthy age-matched controls. The pattern of brain activity differences in our control group looks convincingly similar to those in young healthy adults as demonstrated by Walla et al. [1]. Figures 3 and 4show visualised brain activities of both conditions (with odour and without odour) in the control group for both time windows for which significant effects were found. However, these apparently normal difference brain activity patterns are missing in MCI patients. At this point is has to be emphasised again that this finding is based on a relatively small sample size. However, our selection criteria with respect to patients were very rigorous and conservative and thus supporting significance of possible differences compared to normal controls.


Dysfunctional Incidental Olfaction in Mild Cognitive Impairment (MCI): An Electroencephalography (EEG) Study.

Walla P, Duregger C, Deecke L, Dal-Bianco P - Brain Sci (2011)

LORETA solutions for the early odour-related effect in controls. Maximum brain activity difference between odour versus no-odour can be seen at the left fronto-temporal area.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061781&req=5

f3-brainsci-01-00003: LORETA solutions for the early odour-related effect in controls. Maximum brain activity difference between odour versus no-odour can be seen at the left fronto-temporal area.
Mentions: We tested the hypothesis that MCI patients demonstrate different brain activity patterns related to incidental olfactory information processing compared to age-matched controls due to their known olfactory impairment. This can be confirmed. In comparison to previous findings [1] the present study too revealed significant brain activity differences between the conditions faces without odour and faces with odour in healthy age-matched controls. The pattern of brain activity differences in our control group looks convincingly similar to those in young healthy adults as demonstrated by Walla et al. [1]. Figures 3 and 4show visualised brain activities of both conditions (with odour and without odour) in the control group for both time windows for which significant effects were found. However, these apparently normal difference brain activity patterns are missing in MCI patients. At this point is has to be emphasised again that this finding is based on a relatively small sample size. However, our selection criteria with respect to patients were very rigorous and conservative and thus supporting significance of possible differences compared to normal controls.

Bottom Line: On the other hand, the patient group did not show any such difference activities.None of these were found in MCI patients, although it has to be emphasised that our sample size was rather small.We confirm previous findings about olfactory related dysfunction in patients with MCI and conclude from our findings that even subliminal odour-related information processing is impaired.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, Faculty of Science and Information Technology, University of Newcastle, Callaghan 2308 NSW, Australia. peter.walla@newcastle.edu.au.

ABSTRACT
Our study provides evidence that Mild Cognitive Impairment (MCI) is associated with olfactory dysfunction on both conscious and non-conscious levels. MCI patients and age-matched controls underwent a face processing task during which sympathy decisions had to be made via button presses. Incidentally, some of the faces were associated with a simultaneously presented odour. Although attention was paid to faces, brain activities were analysed with respect to odour versus no-odour conditions. Behavioural differences were found related to overall face recognition performance, but these were not statistically significant. However, odour-related neurophysiology differed between both groups. Normal controls demonstrated brain activity differences between odour and no-odour conditions that resemble difference activity patterns in healthy young participants as described in a previous magnetoencephalography (MEG) study [1]. They showed odour-related activity patterns between about 160 ms and 320 ms after stimulus onset and between about 640 ms and 720 ms. On the other hand, the patient group did not show any such difference activities. Based on previous research we interpret the early odour-related brain activity pattern in controls as being associated with subliminal olfaction and the later activity pattern with conscious olfaction. None of these were found in MCI patients, although it has to be emphasised that our sample size was rather small. We confirm previous findings about olfactory related dysfunction in patients with MCI and conclude from our findings that even subliminal odour-related information processing is impaired.

No MeSH data available.


Related in: MedlinePlus