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We included 81 studies in applying strict inclusion criteria such as:
1. Patients had a clinical diagnosis of AD or PD; 2. Patients were
compared to a healthy control group; 3. Patients and controls were
age-matched; 4. Olfactory function was assessed by means of a
psychophysical olfactory test; 5. Mean and standard deviation of
the tests were reported. Mean effect sizes indicate that AD and PD
patients’ performance is strongly impaired on all olfactory
functions. Indeed, effect sizes through Cohen’s d’s for AD and PD
were respectively 2.05 and 1.52 on identification, 0.92 and 1.29 on
detection thresholds, and 2.59 and 1.00 on recognition. Both groups
presented with stronger impairment on odor identification and odor
recognition tasks than on odor detection threshold tasks (p <0.05).
However, PD patients exhibited stronger impairments on detection
thresholds than AD patients (p = 0.043). These results suggest that
PD patients are more impaired already on low-level perceptual
olfactory tasks, while AD patients are more impaired on higher-
order olfactory tasks relying on specific cognitive processes such as
long-term memory. In conclusion, our results suggest that odor
identification and recognition tests may help differentiate AD and
PD from normal olfactory age-related decline. Johannes Frasnelli is
supported by a postdoctoral fellowship of CIHR.
#P148
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Brainstem autonomic dysfunction in
neurodegenerative disorders
Mussadiq Shah
1,2
, Jean Monro
1
, Elias Keter
1
, Daniel Goyal
1
,
Chris Yeoh
1
, Peter O O Julu
1,2
1
Breakspear Medical Group, Hemel Hempstead, Hertfordshire
London, United Kingdom,
2
Barts and the London NHS Trust,
Whitechapel, London, United Kingdom
Hypothesis and Aims: We hypothesise that the well-documented
disturbances of the balance between cholinergic and
monoaminergic neurones in neurodegerative disorders extends to
the brainstem. We therefore investigated the modulatory effects of
respiratory neurons on cardiac vagal motor neurons during deep
breathing exercises in healthy controls and in patients with
neurodegenerative disorders. Methods and Results: Non-invasive
real time and continuous monitoring of cardiac vagal tone (CVT)
was done at baseline in supine position during quiet breathing
and during deep breathing exercises in 6 healthy controls, 5 male
and 1 female aged 24-40 years to establish the type of central
autonomic modulation during deep breathing. Eight patients with
neurodegenerative disorders, all were suspected of suffering from
multiple system atrophy (MSA). Four males aged 71-73 and 4
females aged 60-67 years were studied. Eight more patients within
these age ranges but without neurodegenerative disorders were also
studied. There were 4 males aged 67-74 and 4 females aged 59-69
years in this group. The results were analysed and compared.
The CVT was measured using the NeuroScope and expressed in
units of a linear vagal scale (LVS). The local ethics committee of
the Imperial College, London, approved the study. Conclusion:
We have shown here that the cholinergic dependant central
respiratory modulation of cardiac vagal motor neurones is impaired
in neurodegenerative disorders. It suggests that cholinergic
interneurones may be affected in the lower brainstem in
neurodegenerative disorders more than it is currently known.
This is new data and requires further investigation whether this
cholinergic dysfunction is related to the early loss of taste and smell
in neurodegenerative disorders. Acknowledgements: Breakspear
Medical Group, Hemel Hempstead, Hertfordshire, London UK.
#P149
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Evidence of Hypergeusia in Burning Mouth Syndrome Patients
Susan E. Coldwell
1,2
, Mark T. Drangsholt
1,2
,
Kimberly H. Huggins
1,2
, Mary K. Scott
2
, Mary K. Hagstrom
3
1
University of Washington Department of Oral Health Sciences
Seattle, WA, USA,
2
University of Washington Department of Oral
Medicine Seattle, WA, USA,
3
University of Washington Regional
Clinical Dental Research Center Seattle, WA, USA
Burning mouth syndrome (BMS) has been defined as burning pain
in the tongue or oral mucous membranes, usually without
accompanying clinical findings. Symptoms of BMS often include
taste phantoms. There are numerous reports in the literature of
increased taste thresholds for the anterior tongue in patients with
BMS. A hypothesis for the etiology of BMS has thus been proposed
suggesting that BMS results from disinhibition of nociceptive input
from the trigeminal nerve following damage to the chorda tympani
branch of the facial nerve (Grushka and Bartoshuk, 2000).
Similarly, taste phantoms may result from disinhibition of gustatory
input from the glossopharyngeal nerve. As part of a larger case-
control study, BMS cases and pain-free controls were given a brief
suprathreshold taste assessment battery that included anterior
tongue and whole-mouth testing. Participants were 20 female
BMS patients (age 33 to 76 yrs) and 32 female pain-free controls
(age 33 to 68 yrs). Participants completed questionnaires including
items on the experience of persistent salty, sweet, sour, bitter, or
metallic taste sensations. Participants used the general Labeled
Magnitude Scale (gLMS) to rate the intensity of tastants (1 M
sucrose, 1 M NaCl, 0.032 M citric acid, 0.001 M quinine HCl)
applied to the lateral, dorsal surface of the anterior tongue as well
as sampled whole-mouth. 10 of 20 BMS cases and
only
1 of 32
controls reported experiencing taste phantoms (p<0.001). BMS
cases gave higher gLMS ratings than did controls for whole-mouth
NaCl, citric acid, and quinine HCl (p’s <0.025). The observed
whole-mouth hypergeusia is consistent with a disinhibition
hypothesis. However, unexpectedly, ratings of tastants applied to
the anterior tongue were comparable in cases and controls, or were
slightly elevated in cases. Acknowledgements: Supported by
federal funds from the National Institute of Dental and Craniofacial
Research, 3R21DE018768-02S1 (PI, Mark Drangsholt) and by
Grant UL1RR025014 from the NIH National Center for
Research Resources.
Abstracts | 77
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