A practical test for retronasal odor identification based on aromatized tablets

BACKGROUND

Olfactory perceptions elicited by odors originating from within the body (retronasal olfaction) play a crucial role in well-being and are often disrupted in various medical conditions. However, the assessment of retronasal olfaction in research and the clinical practice is impeded by the lack of commercially available tests and limited standardization of existing testing materials.

NEW METHOD

The novel ThreeT retronasal odor identification test employs 20 flavored tablets that deliver a standardized amount of odorous stimuli. The items represent common food- and non-food-related odors.

RESULTS

The ThreeT test effectively distinguishes patients with olfactory dysfunction from healthy controls, achieving a specificity of 86% and sensitivity of 73%. Its scores remain stable for up to 3 months (r=.79).

COMPARISON WITH EXISTING METHOD

ThreeT test exhibits a strong correlation with "Tasteless powders" measure of retronasal olfaction (r=.78) and classifies people into healthy and patient groups with similar accuracy. Test-retest stability of ThreeT is slightly higher than the stability of "Tasteless powders" (r=.79 vs r=.74).

CONCLUSIONS

ThreeT is suitable for integration into scientific research and clinical practice to monitor retronasal odor identification abilities.

Null cross-modal effects of olfactory training on visual, auditory or olfactory working memory in 6- to 9-year-old children

Systematic exposure to odours (olfactory training, OT) is a method of smell loss treatment. Due to olfactory system projections to prefrontal brain areas, OT has been hypothesized to enhance cognitive functions, but its effects have been studied predominantly in adults. This study tested OT effects on working memory (WM), i.e., the ability to store and manipulate information for a short time, in healthy children aged 6-9 years. We expected OT to improve olfactory WM and establish cross-modal transfer to visual and auditory WM. Participants performed 12 weeks of bi-daily OT with either 4 odours (lemon, eucalyptus, rose, cloves; OT group) or odourless propylene glycol (placebo group). Pre- and post-training, participants' WM was measured utilizing odours (olfactory WM) or pictures (visual WM) and a word-span task (auditory WM). 84 children (40 girls) completed the study. The analyses revealed no changes in the WM performance following OT. The olfactory WM task was the most difficult for children, highlighting the need to include olfactory-related tasks in educational programmes to improve children's odour knowledge and memory, just as they learn about sounds and pictures. Further neuroimaging research is needed to fully understand the impact of OT on cognitive functions in children.

Olfactory training effects in children after mild traumatic brain injury

OBJECTIVE

Mild traumatic brain injury (mTBI) might impair the sense of smell and cognitive functioning. Repeated, systematic exposure to odors, i.e., olfactory training (OT) has been proposed for treatment of olfactory dysfunctions, including post-traumatic smell loss. Additionally, OT has been shown to mitigate cognitive deterioration in older population and enhance selected cognitive functions in adults. We aimed to investigate olfactory and cognitive effects of OT in the pediatric population after mTBI, likely to exhibit cognitive and olfactory deficits.

METHODS

Our study comprised 159 children after mTBI and healthy controls aged 6-16 years (M = 9.68 ± 2.78 years, 107 males), who performed 6-months-long OT with a set of 4 either high- or low-concentrated odors. Before and after OT we assessed olfactory functions, fluid intelligence, and executive functions.

RESULTS

OT with low-concentrated odors increased olfactory sensitivity in children after mTBI. Regardless of health status, children who underwent OT with low-concentrated odors had higher fluid intelligence scores at post-training measurement, whereas scores of children performing OT with high-concentrated odors did not change.

CONCLUSION

Our study suggests that OT with low-concentrated odors might accelerate rehabilitation of olfactory sensitivity in children after mTBI and support cognitive functions in the area of fluid intelligence regardless of head trauma.

Olfactory training - Thirteen years of research reviewed

The sense of smell is interrelated with psychosocial functioning. Olfactory disorders often decrease quality of life but treatment options for people with olfactory loss are limited. Additionally, olfactory loss accompanies and precedes psychiatric and neurodegenerative diseases. Regular, systematic exposure to a set of odors, i.e., olfactory training (OT) has been offered for rehabilitation of the sense of smell in clinical practice. As signals from the olfactory bulb are directly projected to the limbic system it has been also debated whether OT might benefit psychological functioning, i.e., mitigate cognitive deterioration or improve emotional processing. In this review we synthesize key findings on OT utility in the clinical practice and highlight the molecular, cellular, and neuroanatomical changes accompanying olfactory recovery in people with smell loss as well as in experimental animal models. We discuss how OT and its modifications have been used in interventions aiming to support cognitive functions and improve well-being. We delineate main methodological challenges in research on OT and suggest areas requiring further scientific attention.

Sensory compensation beliefs among blind and sighted individuals

The process of neural and behavioral reorganization following sensory loss is known as sensory compensation. Typically, it is believed that sensory loss is followed by increased acuity of the intact modalities. Indeed, many studies compared blind and sighted individuals' sensitivity of the intact sensory modalities. Yet, it remains poorly understood whether sensory compensation is reflected in the lay beliefs of those, whom it concerns. We examined whether blind and sighted individuals believe that their lack of vision is compensated by increased sensitivity of the intact senses. Study 1 (n = 63) aimed to compare the ratings of sensory sensitivity made by blind and sighted people. Participants rated the sensory sensitivity of a blind population in four modalities (i.e., olfaction, audition, gustation, touch) and compared it to the sensory sensitivity of a sighted population. In Study 2 (n = 191) participants rated their own sensory sensitivity in four modalities. Each participant referred to (1) people of the same sensory status and (2) people of the opposite sensory status. The level of global self-esteem was controlled to verify self-enhancing nature of these beliefs. The results of both studies showed that the beliefs about sensory compensation are shared by blind and sighted participants on group and on individual levels. The self-enhancement underpinning of these beliefs was most pronounced in gustatory sensitivity assessment. Psychological and medical consequences of sensory compensation beliefs are discussed.

q-Powders: a quick test for screening retronasal olfactory disorders with tasteless powders

Purpose

To investigate the clinical utility of q-Powders—a retronasal identification screening test.

Methods

A total of 156 subjects (92 females, mean age: 54.5 years ± 17.3 years) completed a 3-item q-Powders retronasal identification test and a 16-items Sniffin’ Sticks orthonasal identification test. We analyzed whether the q-Powders test could differentiate between subjects with normosmia and subjects with an olfactory disorder.

Results

Our data indicated that subjects with an olfactory disorder scored lower in the q-Powders test than subjects with normosmia. The analyses revealed q-Powders test sensitivity of 84% and a test specificity of 64.9% with a score of 2 points taken as a cutoff for olfactory disorders.

Conclusion

The 3-item q-Powders retronasal test may be used for screening purposes in clinical research.

Level of evidence

4

Olfactory training with Aromastics: olfactory and cognitive effects

Purpose

The olfactory system can be successfully rehabilitated with regular, intermittent stimulation during multiple daily exposures to selected sets of odors, i.e., olfactory training (OT). OT has been repeatedly shown to be an effective tool of olfactory performance enhancement. Recent advancements in studies on OT suggest that its beneficial effects exceed olfaction and extend to specific cognitive tasks. So far, studies on OT provided compelling evidence for its effectiveness, but there is still a need to search for an optimal OT protocol. The present study examined whether increased frequency of OT leads to better outcomes in both olfactory and cognitive domains.

Method

Fifty-five subjects (28 females; M_age = 58.2 ± 11.3 years; 26 patients with impaired olfaction) were randomly assigned to a standard (twice a day) or intense (four times a day) OT. Olfactory and cognitive measurements were taken before and after OT.

Results

OT performed twice a day was more effective in supporting olfactory rehabilitation and interventions targeted to verbal semantic fluency than OT performed four times a day, even more so in subjects with lower baseline scores.

Conclusions

OT is effective in supporting olfactory rehabilitation and interventions targeted to verbal semantic fluency. However, it may be prone to a ceiling effect, being efficient in subjects presenting with lower baseline olfactory performance and lower verbal semantic fluency.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-06810-9.

The contribution of texture contrasts and combinations to food acceptance across cultures

Texture has long been considered an important attribute for food acceptance. However, which specific textural characteristics contribute to overall acceptance of a food is not well understood. It has been suggested that texture contrasts and combinations are a universal feature in giving foods a desirable texture, yet this notion is largely based upon anecdotal data. This study uses multiple survey research methods to assess the importance of texture contrast and combinations across cultures (Poland, U.S.A., and Singapore). Participants (N = 288) completed a survey that included overt measures of food texture contrast importance as well as free response questions regarding texture. The overall importance of texture for food liking was not different across the populations. However, the participants from Singapore and Poland gave more importance to a desirable food having multiple textures than the U.S.A. cohort. When looking at free responses, participants were twice as likely to mention combinations (multiple textures) with a texture contrast when describing foods they liked, in comparison to foods they disliked. This was observed across all three cultures. However, the type and quantity of texture terms used within combinations were different among cultures. For instance, Singaporeans enjoyed more texturally diverse food combinations than the other two cultures. These findings highlight the importance of texture contrasts and combinations in three distinct cultures.

Insulin impairs the anticonvulsive activity of carbamazepine against maximal electroshock-induced seizures in mice

In view of the data indicating that insulin can modify penetration of some drugs across cell membranes and tissue barriers, particularly the blood-brain barrier, the aim of the present study was to evaluate the effect of insulin on both the anticonvulsant activity and the brain concentration of carbamazepine in mice suffering from seizures induced by maximal electroshock. The antiepileptic drug was administered per os in single doses either alone or in combination with insulin given as single intraperitoneal injections. To assess the anticonvulsant activity of carbamazepine the ED50 values were calculated. The results indicate that insulin given in doses up to 2 units/kg did not affect the convulsive threshold, whereas insulin applied at 2 units/kg led to a significant reduction in the anticonvulsant activity of carbamazepine, as judged by an increase in the ED50 value from 16.2 to 41.3 mg/kg. This effect was accompanied by the marked reduction in both the brain and blood concentrations of the drug. It is likely, therefore, that the inhibitory activity of insulin on the anticonvulsive function of carbamazepine is related not only to the effect of the former on the blood-brain transport of the latter, but also to insulin-induced modulation of the serum concentration of the drug.

[Tendinous cords in echocardiographic studies--occurrence, clinical significance]

Tendinous chords inside cardiac ventricles were found in 53 (5.6%) out of 954 individuals examined echocardiographically within one year. Only 30 individuals were further analysed. No marked pathology in the cardiovascular system was found. Tendinous chord was localized in the right ventricle in 7 individuals, in left ventricle in 21, and in both ventricles in 2 subjects. Ventricular arrhythmias were shown in 11 subjects (36.6%) with the aid of a 24-hour ECG monitoring with Holter's technique. They were of the II and IV stage of advancement according to Lown's classification. Ventricular rhythm disorders were seen in both subjects with tendinous chord within left ventricle (7 subjects) and in the right ventricle (4 subjects). Local diastolic disorders with no effect on the ejection fraction were noted in all subjects with false chord and ventricular rhythm disorders. Ventricular cardiac rhythm disorders are being observed in the subjects with the false chord located within the right or the left cardiac ventricle producing local diastole disturbances.

[Treatment of supraventricular paroxysmal tachycardia and auricular flutter by auricular stimulation]

Although the management of supraventricular tachycardias (SVT) and atrial flutter (AF1) with drugs or cardioversion is usually effective, their use in the high risk patient commonly digitalized, may be dangerous. Since the availability of an alternate therapeutic method is desirable, the usefulness of atrial pacing was evaluated in 31 episodes of tachyarrhythmia in 31 patients with varied heart conditions. The arrhythmia diagnosis and the stimulation were done through a right atrial electrode. In most cases the rate of stimulation was higher than that of the atria (up to 400 stimuli per min). Of 17 cases with SVT (four with preexcitation syndrome), pacing led to sinus rhythm (SR) in all, even though it was transient in two. SR was obtained in six of eleven cases of AF1, through a short lasting atrial fibrillation (AF) in three of them. Four patients with paroxysmal atrial tachycardia with A-V block changed to AF. SR was achieved shortly after termination of the procedure in two of the latter. It is concluded that atrial pacing is a valuable therapeutic method since it is effective, it has very low risk specially in digitalized patients, its does not require anesthesia and because it may be used repeatedly in case of recurrence. The technique of atrial pacing permits, in some cases, the identification of the mechanism responsible for the arrhythmia.

[Hemodynamic evaluation in acute myocardial infarct. Application to the treatment of contractile insufficiency syndromes of the left ventricle]

Even though the coronary care units have reduced to a minimum the mortality due to arrhythmias, the syndromes of left ventricular failure are responsible for the greatest part of hospital deaths in patients with acute myocardial infarction. The poor results depend upon the extensive destruction of left ventricular mass. The management in these cases should be directed to improve the performance of viable muscle as well as to preserve thejeopardized ischemic myocardium that is potentially viable. These goals may be adequately pursued by continuous hemodynamic characterization of left ventricular function. The experience of the Coronary Care Unit of the Instituto Nacional de Cardiología de México in the study of 30 of these patients is presented. Hemodynamic evaluations were performed by means of a Swan-Ganz catheter and cardiac output determinations by the thermodilution technique. The studies may be performed with a minimum of risk. Central venous pressure measurements do not adequately indicate the status of the left ventricle. Its function may be evaluated by the use of end diastolic pulmonary artery pressure which reflects, quite accurately, the left ventricular filling pressure in these patients. Continuous hemodynamic monitorization facilitates the proper manipulation of the determinants of ventricular performance (preload, afterload, cardiac rate and contractility) and permits an attempt to improve the balance between available oxygen and myocardial oxygen requirements. Hemodynamic studies and ventricular function curves are presented in selected patients with acute myocardial infarction. The mortality due to left ventricular failure and cardiogenic shock in patients with acute myocardial infarction remains extremely high. However, it is only through the early recognition by continuous hemodynamic monitorization and the aggressive management of the patient with incipient left ventricular failure that the number of survivors may be increased.

[The bradycardia-tachycardia syndrome]

Disorders of the heart rhythm which consist basically of sinus bradicardia or sinus arrest correspond to a syndrome which has been named the sick sinus syndrome. Within the framework of this syndrome, there is a subgroup of alternating atrial bradycardia with episodes of atrial tachyarrhythmia. Generally known as the bradycardia-tachycardia syndrome, this subgroup is both electrophysiologically interesting and therapeutically challenging. This report is concerned with the experience obtained at the emergency ward and coronary care unit of the Instituto Nacional de Cardiología de México on the diagnosis and management of 8 patients with this syndrome. Various underlying heart conditions were present with predominance of ischemic heart disease. The clinical picture was dependent upon the hypoperfusion of vital organs secondary to the cardial arrhythmia. The most common symptoms were derived from cerebral circulatory deficit and coronary insufficiency. Half of the patients had moderate cardiac failure. All patients had spontaneous and transient loss of sinus function which lasted more than 2,000 msec. in seven. The bradycardia had a rate below 50 beats per minute in all cases except one. The tachyarrhythmias observed were atrial flutter, atrial fibrillation and paroxysmal supraventricular tachycardia. Three of the patients had more than one of these these tachyarrhythmias during the period of study. A discussion is made on the diagnosis of this syndrome by means of atrial pacing and interventions which modify either vagal or sympathetic tone. Considerations are also made on the frequent associated abnormality of the A-V functional tissues. Emphasis is placed on the problems encountered in the management of these patients. It is concluded that, in most cases, a satisfactory result may be obtained by the implantation of a permanent demand pacemaker associated to the administration of antiarrhythmic drugs.