Association between olfactory function and quality of life in patients with olfactory disorders: a multicenter study in over 760 participants

BACKGROUND

This cross-sectional, multi-centric study aimed to investigate the differences in quality of life among patients with olfactory dysfunction (OD) of different origin, and to identify factors associated with olfactory-related quality of life (QOL).

METHODS

Seven hundred sixty-three adults were recruited from 8 Smell & Taste clinics in Germany, Switzerland, and Austria. Olfactory-related QOL was assessed by the Questionnaire of Olfactory Disorders (QOD). Olfactory function was assessed with the "Sniffin' Sticks" test; self-assessment was performed with visual analog scales.

RESULTS

Patients with post-infectious and post-traumatic OD showed poorer olfactory-related QOL than patients with sinonasal and idiopathic OD. The olfactory-related QOL was positively associated with the "Sniffin' Sticks" test score, self-assessed olfactory function, disease duration, and age, with younger olfactory dysfunction patients showing lower QOL. Female patients presented with poorer olfactory-related QOL. In addition, the results showed that self-assessment of olfactory function explained more of the variance in olfactory-related QOL than olfactory function evaluated by the Sniffin’ Sticks test.

CONCLUSIONS

In addition to the psychophysical testing results, several factors such as disease cause, disease duration, sex, or self- assessed olfactory dysfunction should be taken into account when assessing the individual severity of the smell loss.

Individual importance of olfaction decreases with duration of smell loss

BACKGROUND

The personal importance of a lost neurologic - motor or sensory - function in several conditions has been shown to decrease as the afflicted patient becomes accustomed to not having that function. It is unknown how the importance of olfaction changes with duration of olfactory dysfunction (OD). The aim of this study was to evaluate the association between duration of smell loss and individual significance of olfaction, and whether this relationship would be modulated by other factors, such as etiology of smell loss.

METHODS

This is a retrospective study including a total 163 subjects with different degrees of olfactory function. Individual significance of olfaction was measured using the Importance of Olfaction Questionnaire (IOQ). Demographics, olfactory function, duration and etiology of OD were evaluated. Group comparisons, bivariate correlations, analyses of variance and multivariate linear regression were applied to detect differences and associations with the outcome measure of IOQ.

RESULTS

A significant negative correlation was found between duration of OD and the IOQ. Other important findings include a significantly higher IOQ in patients with posttraumatic- compared to idiopathic OD and in patients with higher aggravation scores compared to the lower aggravation group. Multivariate regression analysis further confirmed that duration of smell loss was independently associated with IOQ.

CONCLUSIONS

The duration of smell loss is negatively correlated with the individual importance of olfaction, suggesting that patients develop coping mechanisms for adjusting to OD.

Retronasal olfactory testing using candies sent by post and for screening purposes: a feasibility study

BACKGROUND

The olfactory system is able to detect external odours through the orthonasal- and internal odours through the retronasal route. Flavour perception strongly relies on the sense of smell and this back route. In contrast to orthonasal, retronasal olfactory tests (ROT) are less frequently applied, although testing should be recommended for several reasons. The aim of the present investigation was to propose a suitable form of ROT for home-testing (and postal distribution) and evaluate a retronasal screening test.

METHODOLOGY

Initially, 111 participants were tested using a 27-item version of the Candy Smell Test (CST). Fifty-four participants performed retesting, of which 25 subjects did so in a home-setting being supplied with professionally packed "candy-chains". Seven candies were chosen by means of hit rate differences in normosmics and severely hyposmics/anosmics. The 7-CST is designed in a non-forced-choice fashion with same seven flavours to choose from.

RESULTS

For the 27-item CST both groups (subjects performing home-testing and those performing retesting at the clinic) showed highly significant test-rest-reliabilities. The 7-CST was capable of discriminating healthy from diseased subjects when being tested in 116 healthy subjects and 47 patients suffering from olfactory dysfunction.

CONCLUSION

The CST is suitable for home-testing and postal distribution. The new 7-item CST can be valuable for rapidly revealing anosmics. These findings help in further standardizing ROT, may encourage rhinologists to more routinely evaluate retronasal olfactory abilities and pave the way for larger epidemiologic studies also in regard to food preferences and nutritional behaviour.

Testing gustatory function using either a forced-choice or a non-forced-choice paradigm - Does it make a difference?

BACKGROUND

Recently more interest is evolving for research on gustatory function, also due to findings of â€extraoral†taste receptors with postulated participation in a pathogen detection network. Also, bitter taste function seems to be reduced in patients with chronic rhinosinusitis. For testing gustatory function â€taste strips†(TS) have been validated in a forced-choice (fc) and a non-forced-choice (nfc) paradigm and used in several studies. Purpose of the investigation was to evaluate possible differences of named modalities.

METHODOLOGY

Healthy subjects (n=102) with subjective normal gustatory function and patients (n=30) with potential taste dysfunction were included. All participants were tested twice (using TS in four concentrations of sweet, sour, salty, and bitter taste), either starting with a fc or a nfc paradigm.

RESULTS

In tested patients there was a difference between fc and nfc procedure with higher results for bitter in the fc testing procedure, while other qualities did not differ. This effect was also visible in the overall participants with higher scores in the fc procedure for bitter taste.

CONCLUSION

TS are valid to be used in a forced and a non-forced choice paradigm, with bitter taste showing slightly higher scores in forced-choice testing. Future investigators with focus on bitter taste perception should be particularly cautious when comparing results in regard to testing procedure.