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Impact of Olfactory Impairment on Quality of Life and Disability
Takaki Miwa, MD, PhD;
Mitsuru Furukawa, MD, PhD;
Toshiaki Tsukatani, MD, PhD;
Richard M. Costanzo, PhD;
Laurence J. DiNardo, MD;
Evan R. Reiter, MD
Arch Otolaryngol Head Neck Surg. 2001;127:497-503.
ABSTRACT
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Objective To determine whether olfactory loss affects patients' quality of life
or level of disability.
Design Retrospective survey using questionnaire data and clinic database review.
Setting Two university medical center smell and taste clinics.
Patients A total of 1407 patients were tested for smell and taste disturbances
from 1984 through 1998. Surveys were mailed to 1093 patients who had abnormal
test scores; 420 (38.4%) returned completed surveys. Patients were grouped
by self-rated ability to smell as "impaired" (those reporting persisting deficits)
or "improved" (those reporting no smell problem when surveyed).
Main Outcome Measures Response frequencies were compared between the 2 groups for questions
regarding ability to perform common activities of daily living and quality-of-life
issues.
Results Mean (±SD) number of activities of daily living affected by olfactory
loss was 4.70 ± 3.56 for the impaired group and 0.61 ± 1.58
for the improved group (P<.001). Among specific
activities, the most common cited impairments were ability to detect spoiled
food (impaired vs improved groups, 75% vs 12%; P<.001),
gas leaks (61% vs 8%; P<.001), or smoke (50% vs
1%; P<.001); eating (53% vs 12%; P<.001); and cooking (49% vs 12%; P<.001).
Differences in quality-of-life issues were reported primarily in the areas
of safety and eating. Overall satisfaction with life was reported by 87% of
the improved group but only 50% of the impaired group (P<.001).
Conclusions Patients reporting persistent olfactory impairment after previously
documented olfactory loss indicate a higher level of disability and lower
quality of life than those with perceived resolution of olfactory compromise.
INTRODUCTION
A SURVEY BY the National Institute on Deafness and Other Communication
Disorders estimated that more than 2.7 million adults in the United States
(1.4% of the population) have chronic olfactory impairment.1
Causes of these losses include head injury, aging, paranasal sinus disease,
neoplasm, medications, toxic exposure, upper respiratory tract infection,
surgical trauma, and congenital defects.2, 3, 4, 5, 6
Despite the relatively high prevalence, there is a lack of public awareness
regarding this problem. Moreover, limited availability of olfactory testing
centers may hinder patients seeking assistance. Unfortunately, even with medical
attention, there is often little that can be done to restore lost olfactory
function.
In recent years, progress has been made toward elucidating various mechanisms
of olfactory losses and their natural course.7, 8, 9, 10
Despite an improved understanding of olfactory disorders, little is known
about the impact of olfactory impairment on patients' lives. Anecdotal reports
suggest that a significant proportion of olfactory-impaired individuals have
a diminished quality of life (QOL) and ability to perform normal activities
of daily living (ADLs). A few studies have demonstrated this in some patient
populations.4, 10 The relative
scarcity of reports documenting disability or QOL changes relegates olfactory
loss to the status of mere inconvenience rather than that of chronic illness,
as with other sensory impairments such as vision or hearing loss. In the present
study, we used patient databases from 2 large smell and taste centers to examine
the nature and extent of functional disabilities and alterations in QOL experienced
by olfactory-impaired individuals. This information is particularly important
for otolaryngologists, who are frequently involved in the examination and
treatment of such patients.
PATIENTS AND METHODS
PATIENTS AND OLFACTORY TESTING
Patient databases at the smell and taste clinics of the Virginia Commonwealth
University's Medical College of Virginia (MCV) Campus, Richmond, and the Ear
Nose and Throat Clinic of the Kanazawa University Hospital, Kanazawa, Japan,
were accessed to identify patients who had undergone olfactory testing during
a 15-year period (January 1, 1984, through December 31, 1998). A total of
1407 patients (693 from the MCV clinic and 714 from the Kanazawa University
clinic) had been evaluated and were thus eligible to be surveyed. Appropriate
approval was obtained from both parent institutions' Committee on the Conduct
of Human Research before patient contact.
Patients had been examined for olfactory or gustatory dysfunction. All
had undergone quantitative olfactory testing at the time of their clinic visit.
At the MCV clinic, testing was performed by means of the butanol detection
threshold and odor identification tests as described by the Connecticut Chemosensory
Clinical Research Center.11 Testing was performed
at the Kanazawa University clinic by means of the T & T Olfactometer (Daiichi
Yakuhin Sangyo Co, Ltd, Tokyo, Japan) threshold determination technique.12 Patients' degree of olfactory impairment was rated
according to their olfactory function test results as follows: (1) anosmic
(MCV test score, 0-14; Kanazawa test score,  5.6); (2) severe (MCV, 15-44;
Kanazawa, 4.1-5.5); (3) moderate (MCV, 45-64; Kanazawa, 2.6-4.0); (4) slight
(MCV, 65-89; Kanazawa, 1.1-2.5); or (5) normal (MCV, 90-100; Kanazawa, 
1.0). Stratification of patients into 5 levels of olfactory function along
the spectrum from anosmia to normosmia is routinely used with both systems.11, 12
DATA COLLECTION AND ANALYSIS
A questionnaire was developed to determine the present status of subjects'
health and olfactory function. The questionnaire included demographic and
historical information, including general medical history and nature of olfactory
impairment (cause, character, change with time, and severity of loss). The
questionnaire asked patients to indicate whether they felt impaired by their
olfactory loss in the performance of a number of common ADLs. These focused
on activities we perceived as "olfaction-related," such as cooking, detecting
spoiled foods or gas leaks, eating, and others, such as working, socializing,
and playing sports or exercising. The survey also asked questions relating
to patients' enjoyment of life. We term these QOL issues. The questionnaire was first prepared in English and then translated
into Japanese by one of us (T.M.). Surveys were mailed to patients' last known
addresses and were returned to the MCV and Kanazawa University clinics. Data
were recorded and organized by means of a spreadsheet (Microsoft Excel 97;
Microsoft Corp, Redmond, Wash), and statistical analysis was performed with
SPSS (version 9.0; SPSS Inc, Chicago, Ill).
RESULTS
PATIENT DEMOGRAPHICS
Among 1407 patients seen in the 2 smell and taste clinics from 1984
to 1998, 1093 had impaired olfaction on clinical testing and address information
allowing questionnaires to be mailed. Thirty-two questionnaires were returned
with notification that the patient was no longer alive and 627 were never
returned. Of the 434 patients who returned questionnaires, 14 were excluded
for incomplete survey responses. Thus, 420 (38.4%) of the mailed surveys (312
from the Kanazawa University clinic and 108 from the MCV clinic) were complete
and available for study.
The demographic characteristics of all study subjects are shown in Table 1. All had some degree of olfactory
impairment documented during their clinic visit. The patients were grouped
as "improved" (no smell problem at time of survey) or "impaired" on the basis
of their response to the survey question "Do you have problems with your sense
of smell (yes or no)?" The 2 groups were demographically matched with the
exception of race (Table 1). There
was no difference between the average ages for the impaired (mean, 59.6 years;
range, 9-87 years) and improved (mean, 57.1 years; range, 20-87 years) groups
(P = .19, t test).
OLFACTORY STATUS
Subjective and objective differences in olfactory function between the
2 groups were evaluated in several ways. The survey asked patients to subjectively
rate their ability to smell on a scale of 0 (cannot smell) to 10 (normal).
This number was termed the patient's smell score.
Mean smell scores were 8.96 and 2.38, with medians of 10 and 2, for the improved
and impaired groups, respectively (P<.001). None
of the 345 subjects in the impaired group rated their ability to smell as
10 (normal). The degree of olfactory impairment determined by quantitative
testing at the time of clinic evaluation was compared between groups. In the
improved group, 52.0% of patients had tested as having slight or moderate
impairment, while in the impaired group only 24.6% had this level of impairment
(difference significant by Pearson  2, P<.001). Only 29.3% of the improved group, but 55.4% of the impaired
group, tested as being anosmic. Of the anosmic patients, 72.7% (16/22) in
the improved group, but only 7.9% (15/191) in the impaired group, reported
that their sense of smell had improved between the time of testing and the
time of survey. Overall, 58.7% (44/75 patients) in the improved group, but
only 14.8% (51/345) in the impaired group, reported improvement between testing
and survey.
The subjective smell scores were compared with the objective measurements
of olfactory impairment determined by testing in the clinic. The correlation
between patient smell scores and olfactory function test results was significant
by Pearson 2 testing (r = -0.47; P<.001). Of 104 patients reporting a smell score of
0 (anosmic), 85.6% tested as being anosmic at the time of the clinic visit.
The characteristics of the olfactory disturbance experienced by subjects
in the impaired group are shown in Table
2. Among the 345 subjects in this group, 96.4% (268/278 patients
who reported the duration of their smell problem) had had their olfactory
disturbance for longer than 1 year. Although 54.2% reported no change in olfaction,
14.8% reported improvement and 9.9% reported worsening since the time of their
smell and taste clinic evaluation. Fluctuation in sense of smell was noted
by 15.7%. When asked about their type of smell problem, 11.9% reported alteration
in the quality of known odors (dysosmia), while 4.1% noted phantom odors (phantosmia).
Approximately half reported complete loss of smell (anosmia). The most common
causes of olfactory disturbance among this group were nasal or sinus disease
(21.4%), head or facial injury (17.1%), documented upper respiratory tract
infection (17.1%), and unknown (28.4%).
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Table 2. Olfactory Status of 345 Patients in Impaired Group
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IMPACT OF OLFACTORY LOSS ON ADLS
Figure 1 shows the percentage
of subjects in each group who indicated compromise in the ADLs queried by
the survey. The most commonly cited activities impaired by olfactory loss
for the impaired group were detection of spoiled foods (75%), detection of
gas leaks (61%), eating (53%), detection of smoke (50%), cooking (49%), buying
fresh food (36%), and using perfume or colognes (33%). Differences between
the response frequencies observed in the impaired and improved groups were
statistically significant by Pearson 2 test (P<.05) for all of the listed ADLs, with the exception of sports
or exercise (P = .14). The number of ADLs affected
by olfactory loss in each patient was termed the ADL disability
score. Patients in the impaired group had significantly greater ADL
disability scores (mean ± SD, 4.70 ± 3.56) than those in the
improved group (0.61 ± 1.58; P<.001 by t test). The distributions of ADL disability scores for
both groups are shown in Figure 2.
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Figure 1. Percentage of subjects reporting
impairment in selected activities of daily living.
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Figure 2. Histogram showing the number of
activities of daily living (ADL) affected by olfactory impairment reported
by each subject.
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IMPACT OF OLFACTORY LOSS ON QOL
Figure 3 lists the QOL issues
queried by the survey most frequently reported to be affected by olfactory
impairment. Safety issues such as worrying about gas leaks, fire, and cleaning
solution vapors were frequently cited, with these response rates all differing
significantly (t test, P<.05)
from the improved group. Personal hygiene issues also generated high response
frequencies, although concern about breath and body odor was the only one
to achieve statistical significance when compared with the improved group.
Eating issues were also frequently noted, the most common being altered taste
for food, less enjoyment from eating, and preferring food spicier. More than
25% of those in the impaired group indicated that they enjoyed life less than
they used to, although this was not significantly different than in the improved
group (t test, P = .90).
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Figure 3. Percentage of subjects reporting
impairment in selected quality of life issues.
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We also asked patients to rate their global satisfaction with life as
"very dissatisfied," "somewhat dissatisfied," "neither satisfied nor dissatisfied,"
"somewhat satisfied," or "very satisfied." Eighty-seven percent of those in
the improved group, but only about 50% of those in the impaired group, reported
being either very or somewhat satisfied with life (Figure 4). Conversely, only 3% in the improved group, but 34% in
the impaired group, reported being either very or somewhat dissatisfied with
life (Figure 4). These differences
in level of satisfaction with life between the improved and impaired groups
were significant by Pearson 2 test (P<.001).
An analysis of all patients surveyed showed that there was a clear trend toward
greater overall satisfaction with life as the patient-reported smell score
increased (Pearson 2, P<.001).
There were, however, no significant differences in the level of dissatisfaction
when patients were grouped by age, sex, comorbid illnesses, work status, or
level of education. The same finding was obtained when the impaired group
was evaluated alone.
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Figure 4. Level of overall satisfaction
with life reported by subjects in both groups.
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COMMENT
Both the medical and lay communities have historically neglected the
chemical sense of olfaction. Given the scarcity of successful treatments,
the perception exists that the diagnosis of olfactory disorders is of little
utility. At present there are fewer than 10 smell and taste research centers
in the United States capable of thoroughly diagnosing and characterizing olfactory
deficits. This compares with thousands of centers nationwide dedicated to
the diagnosis and treatment of disorders of hearing and vision. The lay public
remains uninformed, since most medical practitioners have limited experience
with olfactory disorders and seldom know where to refer such patients for
evaluation of their deficit. As such, people with disorders of olfaction are
given little support in dealing with their problem.
The chemical senses have important safety functions such as the early
detection of fire, gas leaks, spoiled foods, or dangerous fumes, as well as
hedonic functions such as the assessment of the palatability of foods and
beverages and the detection of fragrances or aromas. While these functions
may be less vital to a person's well-being and functionality than vision or
hearing, their loss may still negatively impact a person's QOL and potentially
their level of disability. Previous reports have documented olfactory losses
from a wide variety of injuries and disease processes1, 3, 4, 5, 6, 13;
however, few have systematically evaluated the effects of such losses on patients'
QOL and disability.
A retrospective study of 750 patients tested at the University of Pennsylvania
concluded that "chemosensory dysfunction influences quality of life."4 In particular, patients with dysosmia or dysgeusia
had higher scores on the Beck Depression Inventory, indicating more severe
depression, than patients without these conditions. In addition, patients
with chemosensory dysfunction reported reduced body weight, appetite, and
psychological well-being. Heald and coworkers10
found that the degree of patient-reported chemosensory dysfunction correlated
with lower scores on standardized measures of health and QOL in individuals
infected with human immunodeficiency virus.10
Human immunodeficiency virus–infected individuals with chemosensory
complaints had significantly lower QOL scores in all tested domains, including
physical and social function, general health perception, mental health, and
energy and fatigue, compared with human immunodeficiency virus–infected
counterparts without chemosensory impairment. Other studies have noted relationships
between olfaction and health-related issues that likely impact individuals'
QOL, such as depression, appetite, and nutritional intake.14, 15, 16
The present study sought to determine the impact of olfactory disturbance
on patients' perceived level of disability and QOL. Given the hedonic influence
of olfaction on human existence, we believed a patient-completed survey was
the most relevant instrument to evaluate patients' disability and QOL. Use
of a patient-completed survey as the sole instrument in assessing QOL and
disability potentially introduces bias. However, by comparing 2 demographically
similar groups differing primarily by self-reported olfactory status at the
time of survey, the impact of this effect should be minimized.
There are several means whereby a selection bias might have been introduced
into this study. First, patients presenting to a smell and taste clinic might
represent olfactory-impaired individuals who feel more compromised by their
deficit. The data might then overstate the true impact of olfactory loss.
However, the 2 study groups were both composed of subjects who had previously
sought help. By comparing disability and QOL between these groups, this effect
should be minimized. Second, 627 (57.4%) of the 1093 mailed surveys were never
returned, suggesting a possible sampling bias. It is possible that those not
returning surveys were either not affected by their olfactory loss, leading
to overstatement of our results, or severely affected by their olfactory loss,
leading to understatement of our results. As the 2 study groups were both
composed of subjects who returned surveys, we believe this effect is also
minimized. It is possible that a significant proportion of the 627 unreturned
surveys were not returned because the subject had moved and the receiving
party did not forward the survey. This is likely, as the average time between
clinic visit and survey for our patient population was more than 8 years.
The 2 study groups differed by patient-reported level of olfactory function
at the time of survey. Previous studies have reported poor correlation between
patient-reported and objectively measured degrees of olfactory impairment.15 However, our results show a strong correlation between
the patient-reported smell score and the results of olfactory testing performed
at the time of evaluation at the smell and taste clinic. This is despite the
long average (±SD) time interval (8.08 ± 5.01 years) between
testing and survey completion. This correlation was likely achieved because
(1) patients in the improved group had better olfactory function at the time
of clinic visit (52.0% had a slight or moderate loss determined by testing)
compared with patients in the impaired group (only 24.6% had slight or moderate
loss) and (2) more patients (58.7%) in the improved group reported improved
sense of smell since the time of testing than patients in the impaired group
(14.8%). Thus, on average, subjects in the improved group started with better
olfactory function at the time of testing and were also more likely to have
had improvement between the time of testing and survey than subjects in the
impaired group. Therefore, the impaired group represents a population of olfactory-impaired
individuals, while the improved group represents a group of mildly or non–olfactory-impaired
individuals who had previously experienced olfactory loss.
The study groups also differed significantly in terms of racial distribution.
We cannot discount the possibility that this might introduce a cultural bias
into the nature of subject responses, such that whites are more likely to
complain of olfactory losses than Asians/Pacific Islanders or vice versa.
Potential differences in impact of olfactory losses between the Japanese and
American subjects will be the subject of a forthcoming study. However, we
believe the disparity in racial distribution between the groups is most likely
the result of the differing histories and referral patterns of the 2 smell
and taste clinics involved in the study. At the MCV clinic, where no study
patients were Asians/Pacific Islanders, very few patients are referred to
rule out olfactory losses, because of the restrictive nature of the US health
care system in terms of patient referrals. Also, this clinic was previously
associated with the institution's head injury unit, and thus 27% of patients
had head or facial injury as the cause of olfactory loss, while only 23% indicated
nasal or sinus disease or respiratory infection. Traumatic olfactory losses
generally tend to be more severe or permanent than those caused by nasal or
sinus disease.4 Thus, 92% of the subjects from
the MCV clinic were included in the impaired group, and only 8% were included
in the improved group, as most study subjects from this site either had more
severe olfactory losses at the time of testing or did not improve with time.
At the Kanazawa University clinic, where all study patients were Asians/Pacific
Islanders, far more patients are referred to rule out olfactory losses, as
the Japanese health care system is less restrictive in terms of patient referrals.
Also, as this clinic was formed within the institution's Department of Otolaryngology–Head
and Neck Surgery, there were more patients at this site with olfactory losses
from nasal or sinus disease or documented upper respiratory tract infection
(45%) than from head injury (14%). Consequently, more patients had less severe
or transient olfactory losses. As a result of both of these factors, 21% of
the subjects from this site were included in the improved group and 79% in
the impaired group.
In this study, subjects reported that their ability to perform or participate
in a number of daily activities was hindered by their olfactory loss. Although
our survey made no effort to have subjects quantify their degree of disability,
we believe that the difference between the impaired and improved groups shown
in Figure 1 and Figure 2 supports this statement. Most striking was the high percentage
of subjects indicating difficulty detecting spoiled foods, gas leaks, or smoke—activities
considered "safety functions" of olfaction. These deficits are significant
given the widespread use of gas grills, water heaters, furnaces, and appliances,
and the resultant risk of fire in the home. Thirty-seven percent of survey
respondents reported at least 1 smoker in the house, thus further increasing
the risk of injury or mortality to these olfactory-impaired individuals.17 Subjects also frequently reported difficulties with
food-related activities (eating, cooking, buying fresh food, and going out
to eat) and hygiene-related activities (using perfumes, colognes, or scented
detergents or soaps, detecting soiled diapers, and housecleaning). These activities
are not critical in terms of safety or survival but are important to most
people in maintaining a desirable lifestyle. Finally, few subjects reported
an effect of their olfactory loss on work or hobbies such as gardening or
socializing. However, the effect of olfactory loss on subjects' ability to
work might depend greatly on vocation. It might be inferred from the previous
data that workers in vocations involving any of the above activities, such
as food service workers, firefighters, home appliance or heating technicians,
utility workers, or retailers of perfumes and soaps, might be compromised
in their ability to perform their jobs.
The present study clearly indicates a negative impact of olfactory deficits
on patient-perceived QOL. The areas that stand out most are safety and eating,
as shown in Figure 3. The high rate
of reported concern about gas leaks and fire mirrors patients' reported reduced
ability to detect gas leaks and smoke. Patients reported altered taste for
food and decreased enjoyment of eating. Although more than 50% of subjects
in the impaired group reported increased concern about breath or body odor,
concerns about other hygiene issues were not significantly different from
those of subjects in the improved group. While these concerns might not seem
significant, together they may be a factor contributing to the increased rate
of depression seen in olfactory-impaired individuals.14
Despite the noted negative impact on multiple QOL issues among subjects
with olfactory losses, the percentage of subjects in both the impaired and
improved groups reporting decreased "enjoyment of life" overall was the same
(approximately 25%). However, when subjects were asked to rate their overall
"satisfaction with life," responses between the 2 groups differed significantly
(Figure 4). Moreover, among all
subjects, the greater the degree of olfactory loss, the lesser the degree
of satisfaction with life. This trend could not be accounted for by subject
age, sex, work status, level of education, or comorbid illnesses. The source
of disparity between these 2 findings is unclear. However, the response frequency
for these 2 questions—only 24% for the "enjoyment of life" question
but 94% for the "satisfaction with life" question—strongly suggests
a selection bias, making the later finding more reliable.
In conclusion, the present study used the patient databases from 2 large
university smell and taste centers to quantify the impact of olfactory loss.
Olfactory-impaired individuals reported considerable disability and reduced
QOL. Evaluation of suspected olfactory deficits should thus be considered.
Although treatment options for olfactory disturbances remain limited, thorough
assessment is potentially useful for purposes of patient counseling, particularly
with regard to safety issues, and for determination of disability and monitoring
for interrelated conditions such as depression. The otolaryngologist, who
is uniquely capable of evaluating nasal and thus olfactory anatomy and function,
must be aware of the impact of olfactory dysfunction on patients' lives.
AUTHOR INFORMATION
Accepted for publication September 22, 2000.
This study was supported in part by grant 98-03-034 from the Univers
Foundation, Tokyo, Japan.
Presented at the annual meeting of the Association for Chemoreception
Sciences, Sarasota, Fla, April 29, 2000.
From the Department of Otorhinolaryngology, School of Medicine, Kanazawa
University, Kanazawa, Japan (Drs Miwa, Furukawa, and Tsukatani), and Department
of Otolaryngology–Head and Neck Surgery, Medical College of Virginia,
Virginia Commonwealth University, Richmond (Drs Costanzo, DiNardo, and Reiter).
Corresponding author and reprints: Evan R. Reiter, MD, Department
of Otolaryngology–Head and Neck Surgery, PO Box 980146, Medical College
of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0146
(e-mail: ent{at}hsc.vcu.edu).
REFERENCES
| |
1. Hoffman HJ, Ishii EK, MacTurk RH. Age-related changes in the prevalence of smell/taste problems among
the United States adult population: results of the 1994 disability supplement
to the National Health Interview Survey (NHIS). Ann N Y Acad Sci. 1998;855:716-722.
FULL TEXT
|
ISI
| PUBMED
2. Ship JA, Pearson JD, Cruise LJ, Brant LJ, Metter EJ. Longitudinal changes in smell identification. J Gerontol A Biol Sci Med Sci. 1996;51:M86-M91.
3. Costanzo RM, DiNardo LJ, Zasler ND. Head injury and olfaction. In: Doty RL, ed. Handbook of Olfaction and Gustation. New York, NY: Marcel Dekker Inc; 1995:493-502.
4. Deems DA, Doty RL, Settle RG, et al. Smell and taste disorders, a study of 750 patients from the University
of Pennsylvania Smell and Taste Center. Arch Otolaryngol Head Neck Surg. 1991;117:519-528.
FREE FULL TEXT
5. Doty RL. A review of olfactory dysfunctions in man. Am J Otolaryngol. 1979;1:57-79.
PUBMED
6. Schiffman SS. Taste and smell in disease (first of two parts). N Engl J Med. 1983;308:1275-1279.
ISI
| PUBMED
7. Spielman AI. Chemosensory function and dysfunction. Crit Rev Oral Biol Med. 1998;9:267-291.
FREE FULL TEXT
8. Duncan HJ, Smith DV. Clinical disorders of olfaction: a review. In: Doty RL, ed. Handbook of Olfaction and Gustation. New York, NY: Marcel Dekker Inc; 1995:345-365.
9. Schiffman SS. Taste and smell losses in normal aging and disease. JAMA. 1997;278:1357-1362.
FREE FULL TEXT
10. Heald AE, Pieper CF, Schiffman SS. Taste and smell complaints in HIV-infected patients. AIDS. 1998;12:1667-1674.
FULL TEXT
|
ISI
| PUBMED
11. Cain WS, Gent J, Catalanotto FA, Goodspeed RB. Clinical evaluation of olfaction. Am J Otolaryngol. 1983;4:252-256.
ISI
| PUBMED
12. Takagi SF. Human Olfaction. Tokyo, Japan: University of Tokyo Press; 1989:35-58.
13. Ophir D, Guterman A, Gross-Isseroff R. Changes in smell acuity induced by radiation exposure of the olfactory
mucosa. Arch Otolaryngol Head Neck Surg. 1988;114:853-855.
FREE FULL TEXT
14. Satoh S, Morita N, Matsuzaki I, et al. Relationship between odor perception and depression in the Japanese
elderly. Psychiatry Clin Neurosci. 1996;50:271-275.
PUBMED
15. Mattes RD, Cowart BJ. Dietary assessment of patients with chemosensory disorders. J Am Diet Assoc. 1994;94:50-56.
FULL TEXT
|
ISI
| PUBMED
16. Schiffman SS. Taste and smell in disease (second of two parts). N Engl J Med. 1983;308:1337-1343.
ABSTRACT
17. Barillo DJ, Goode R. Fire fatality study: demographics of fire victims. Burns. 1996;22:85-88.
FULL TEXT
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ISI
| PUBMED
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