Paul C. Goodenough

Comparison of Subjective Perception with Objective Measurement of Olfaction

OBJECTIVE: To see if nasal peak inspiratory flow rate and subjective sense of smell had any correlation with olfactory thresholds. STUDY DESIGN AND SETTING: A cohort study of 186 normal volunteers was recruited from among staff and visitors at a university hospital. Olfactory thresholds were detected for each subject (103 with eucalyptol and 83 with phenethyl alcohol), along with nasal peak inspiratory flow (PIFR). Subjective sense of smell, along with nasal symptoms, mood, and alertness, were recorded on visual analogue scores. RESULTS: Subjective perception of smell had no correlation with olfactory thresholds detected (P = 0.4057) and the other subjective measures also had no correlation. There was a significant relationship of PIFR to thresholds in the group tested with phenethyl alcohol (P = 0.002). CONCLUSION: As with the sensation of nasal patency, the self-assessment of a subjects sense of smell has poor correlation with their actual olfactory ability. SIGNIFICANCE: A patients history cannot be relied upon when determining their olfactory ability and formal testing should be performed. EBM rating: A-1b

Which variables matter in smell tests in the clinic

BACKGROUND Testing of olfactory thresholds in the clinic is becoming more common, with commercially produced tests now available. The effect of common potential variables in the clinic setting on these results is unclear. If many variables must be controlled, tests become more complex and a universally accepted olfactory test becomes less likely. OBJECTIVES The aim of this study was to determine which potential variables the clinician needs to consider when testing olfaction in the out-patient clinic. METHODS The study was conducted in a clinic setting at a university hospital, using 103 normal volunteers, comprising staff members and patients and relatives from the ENT clinic waiting room. The subjects recruited had no active rhinological complaints, were not taking any medications and were aged between 16 and 70 years. An olfactory threshold was established for each subject for the odour eucalyptol. Gender, smoking status, age, peak nasal inspiratory flow, ambient temperature and relative humidity were all recorded. RESULTS For eucalyptol, the distribution of values for olfactory thresholds in the normal population lies around the concentration 10(-3) log vol/vol. There was no significant effect of smoking status, tester, ambient temperature or humidity on the thresholds obtained. CONCLUSIONS The above variables do not have a significant effect on olfactory thresholds elicited in the clinic. The clinician therefore need not attempt to control these factors when testing olfaction in the out-patient setting. These findings bring the implementation of a universal, reliable and easily administered measurement of olfaction a step closer.

Olfactory clearance: what time is needed in clinical practice?

OBJECTIVE To determine olfactory adaptation and clearance times for healthy individuals, and to assess the effect of common variables upon these parameters. STUDY DESIGN AND SETTING Fourteen healthy volunteers were recruited for a series of tests. Their initial olfactory threshold levels for phenethyl alcohol were determined. After olfactory exposure to a saturated solution of phenethyl alcohol (i.e. olfactory adaptation), the time taken for subjects to return to their initial olfactory threshold was then recorded (i.e. olfactory clearance). Visual analogue scale scores for subjective variables were also recorded. RESULTS The 14 subjects performed 120 tests in total. Despite consistent linear trends within individuals, olfactory clearance times varied widely within and between individuals. The mean olfactory clearance time for phenethyl alcohol was 170 seconds (range 81-750). Univariate analysis showed a relationship between olfactory clearance times and age (p = 0.031), symptoms (p = 0.029) and mood (p = 0.048). CONCLUSIONS When testing a persons sense of smell in a clinical setting, recent exposure to similar smells should be noted, and a period of 15 minutes needs to be allowed before retesting if using phenethyl alcohol. Other variables need not be controlled, but greater clearance time may be needed for older patients.

What is the short term effect of perfumes on olfactory thresholds

OBJECTIVES Body sprays and perfumes are commonly worn by patients attending ENT out-patients clinics. Their effect on performance in olfactory testing is unknown. The aim of this study was to determine whether olfactory thresholds are altered by the presence of such fragrances. MATERIALS AND METHODS One hundred and sixty healthy volunteers, aged 18 to 65 years, underwent olfactory thresholds testing. Each was then exposed to one of four strong perfumes, applied in a facemask for two minutes, and the thresholds were retested. RESULTS AND ANALYSIS All olfactory thresholds worsened after being exposed to the strong perfumes of Lynx and Impulse body sprays, with the strongest effect being on olfactory detection of phenylethyl alcohol (p<0.001). CONCLUSIONS Strong perfumes can have a negative effect on olfactory thresholds. SIGNIFICANCE Patients attending olfactory threshold testing need to be advised not to wear body sprays or perfumes.

The Leicester Olfactometer

Problem The objective of this study was to develop a useful and cost-effective olfactometer for routine clinical use. The apparatus was developed to provide a standardized threshold test for patients with olfactory disorders presenting in the ENT clinic. Methods A prospective study of olfactory thresholds in 48 healthy volunteers on 2 consecutive occasions, undergoing quantitative testing with an olfactometer. Further studies of 10 subjects performing 20 tests and 100 subjects performing a single test were also performed. An olfactometer was designed to deliver a semi-automated threshold test for an odor. It was designed as a device containing 8 logarithmic dilutions of an odor along with a control valve operated by software from a laptop computer. Common potential variables for olfactory threshold testing were considered including peak inspiratory flow rate and smoking status. The odors used for the studies were phenethyl alcohol (PEA) and eucalyptol. Subjects were asked to perform 2 tests within 1 month of each other and the mean threshold score for each test was calculated to help derive a test-retest score. Results Consistent olfactory thresholds for PEA were achieved with a mean concentration of 10–4. Test-retest reliability scores for the olfactometer were rx = 0.78 (95% CI 0.67 to 0.89). Common variables thought to affect olfactory testing including peak inspiratory flow rate and smoking were not found to have a significant effect on the threshold scores. Conclusion The Leicester Olfactometer provides a simple and cost-effective method of reliably assessing olfactory thresholds in the outpatient clinic. Significance Routine testing of olfaction can be provided with a sophisticated yet user friendly format that overcomes the expense of single use test kits and other commercially available kits. Support Departmental research funds used.

R152: Olfactory Adaptation and Clearance in Clinical Practice

datella infections in otolaryngology. CONCLUSION: Staphylococcus aureus was the most common pathogen obtained through nasal culture. Environmental allergy was further correlated with having a positive bacterial infection. Allergic disease is known to alter the upper respiratory tract environment somehow making bacterial infection more likely. The important emergences of novel pathogens are more likely encountered in allergic patients. SIGNIFICANCE: Allergic disease has a significant effect on the health of the upper respiratory tract and influences predisposition to bacterial infection. Nasal culturing is a simple procedure that provides the otolaryngologist with specific patient information as well as community trends in the emergence of various pathogens.

The Effects of Sensory Deprivation on Olfactory Thresholds

PROBLEM: The aim of this study was to determine if olfactory thresholds are influenced by removal of other sensory inputs, namely hearing and sight. METHODS: A prospective study was conducted whereby 50 consecutive olfactory threshold tests in total where performed on four subjects (mean age of 38 years; range 29 years to 60 years) over a three-month period in 2006. Each subject underwent threshold testing with the odor phenethyl alcohol using a computer-driven olfactometer device. Subjects were tested both with a blindfold and ear-defenders, and then without, and this order was randomised. These olfactory thresholds were compared and analysed for a statistical difference. RESULTS: There was no significant difference between the olfactory thresholds performed with visual and auditory deprivation, and the olfactory thresholds without visual and auditory deprivation (p 0.01). CONCLUSION: Olfactory thresholds are not significantly influenced by visual or auditory deprivation. SIGNIFICANCE: Olfactory testing in the office can therefore be undertaken accurately without the need to address these factors.

P172: Can Strong Perfumes Affect Our Olfactory Thresholds

oculomotor nerve palsy caused by paranasal-sinus desease. Clinical course and computed tomography (CT) image are documented, and pathogenesis relating to local anatomy is discussed. METHODS: Retrospective case report and review of pertinent literature. RESULTS: Report of three cases of isolated oculomotor nerve palsy caused by paranasal-sinus desease. All the patients complained of double vision and had unilateral disturbance of ocular movement and ptosis, but no visual impairment in opthalmologic examination. In two cases, CT demonstrated soft tissue density (STD) in the posterior ethmoid and the sphenoid sinuses and also inside the ipsilateral anterior clinoid precess (ACP) of sphenoid bone. In the remaining case, CT showed STD in the ethmoid sinus and pneumatization in the ACP. Endoscopic sphenoidectomy was performed on the former two cases, and the last case was treated conservatively with steroid and antibiotics. Their ocular movement returned to normal approximately one month later. In all the cases, CT demonstrated a bony defect at the inferior wall in ACP, which is adjacent to the superior orbital fissure. CONCLUSIONS: Since the oculomotor nerve runs just under the ACP, the authors speculate that compression and/or inflammation through the pneumatized ACP might easily cause isolated oculomotor nerve palsy as in the present cases.