Biomedical subjects

S Nordin

Publications and source records attributed to S Nordin.

35 records · Page 2Linked to original sources

PubMed1997

Olfactory dysfunction for pyridine and dementia progression in Alzheimer disease.

OBJECTIVE: To investigate whether odor detection sensitivity for pyridine, suggested by previous research not to be affected, is impaired in Alzheimer disease (AD) and whether an association exists between odor threshold and both degree of dementia and rate of dementia progression in AD. METHOD: The method of constant stimuli was used to determine odor thresholds for pyridine in 18 patients with AD (Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria) and 16 healthy elderly control subjects. All participants were carefully examined with medical and neuropsychological tests. RESULTS: Six patients with AD but none of the controls were anosmic (total olfactory loss) to pyridine, and the 12 nonanosmic patients had significantly higher detection thresholds (50% probability for detection, 323 parts per billion [ppb]) than did the controls (50% probability for detection, 105 ppb). In addition, an association was found between odor threshold and both degree of dementia and rate of dementia progression in AD. CONCLUSIONS: In contrast to previous findings, our results provide evidence that odor sensitivity in AD is impaired for pyridine. Odor sensitivity, in addition to other suggested predictors of progression rate, may be of interest for defining subgroups of AD or for clinical prognostic judgments of single patients.

Aged↗

PubMed1997

Perceptual learning in olfaction: professional wine tasters versus controls.

By having professional wine tasters and controls perform olfactory tasks of absolute detection (1-butanol), discrimination (lemon and cloves), and identification (common household odors), the present two experiments studied (a) if perceptual odor learning takes place from odor experience acquired under nonlaboratory conditions, (b) if this learning generalizes to odors for which experience is limited, and (c) if generalized learning can be referred to increased general interest for odors that increases attention to odorous features. The results showed that whereas wine tasters were not better than controls on detection, they were superior to controls on discrimination and identification, the latter due to only a few odors. Ratings of experience with certain odors during professional evaluation suggest that generalized perceptual learning may take place in discrimination but not in identification. Wine tasters did not show more general interest for odorous features than did controls. The nonsuperiority in detection may be explained by the fact wine tasters have no professional experience of a detection task per se, implying that perceptual odor learning does not generalize from the olfactory tasks of discrimination and identification to detection.

Adult↗

PubMed1997

Odor learning, recall, and recognition memory in young and elderly adults.

use of an odor learning test and the California Verbal Learning Test in young and elderly adults enabled comparison of age-related effects on recall and recognition memory. Assessment of odor identification further enabled study of which odor function (recall, identification, recognition) is most affected by aging, the odor functions' interrelationships, and predictors of odor recall. Results suggested that both recall and recognition were significantly affected by aging and that the odor-recall decline cannot simply be referred to poor identification. Very similar age-related effect sizes were found for the 3 types of odor functions. Finally, the combined ability to encode, store, and retrieve odors appears to predict overall recall performance (including its identification component) better than do identification and recognition.

Adolescent↗

PubMed1997

Chronobiology of nasal chemosensitivity: do odor or trigeminal pain thresholds follow a circadian rhythm?

Odor and trigeminal pain thresholds were studied four times each at 24:00, 04:00, 08:00, 12:00, 16:00 and 20:00 h in randomized order on different days in five healthy male volunteers. No circadian rhythm of olfactory or trigeminal thresholds were observed. However, the variability of odor, but not pain thresholds, increased from 04:00 h (thresholds between 0.4 and 1.2 p.p.m.) to 16:00 h (thresholds between 0.1 and 2 p.p.m.). It is hypothesized that environmental influences contribute to this increase in variance.

Adult↗

PubMed1996

Prevalence and assessment of qualitative olfactory dysfunction in different age groups.

The prevalence of parosmia and phantosmia among 363 chemosensory and nasal/sinus patients was studied, as was the accuracy with which our clinical questionnaire could assess these dysfunctions. We then investigated whether patients with parosmia or phantosmia, matched for odor intensity, perform poorer on odor identification than do patients with no dysosmia. More than 40% of the study group evidenced either parosmia (18.7%) and/or phantosmia (25.6%), a finding that suggests that more attention should be paid by the medical practitioner in addressing qualitative olfactory dysfunction. Furthermore, it appears that assessment of these dysfunctions may aid in differential diagnosis, and that questionnaires can be used with reasonable validity irrespective of the patient's age. Finally, the results imply that parosmia may be reflected in a discrepancy between odor identification and detection.

Adult↗

PubMed1996

Hip configuration and function in bladder exstrophy treated without pelvic osteotomy.

Nine children with congenital bladder exstrophy treated without pelvic osteotomy were analyzed clinically and radiologically at a mean age of 13 years (range 9-16 years). The acetabular and femoral version angles were measured by computed tomography (CT) imaging. Two of the children had a slight waddling gait, but none of them had any pain and they could participate in sports without problems. They had a normal range of hip movements and a normal foot progression angle. The acetabulum was retroverted by an average of 5 degrees, but was balanced by an increased anteversion of the femur which on the average was 10 degrees-20 degrees higher than normal. The femoral head in all hips was spherical, and no hip showed dysplasia. In bladder exstrophy, retroversion of the acetabulum was balanced by an increased anteversion of the femur, resulting in a normal range of hip movements and a normal gait in later childhood.

Adolescent↗

PubMed1995

Sensory- and memory-mediated olfactory dysfunction in Huntington's disease.

Neuropathology in Huntington's disease (HD) known to project to areas that process olfactory information raises the questions of which olfactory function, if any, is most affected in HD, and how to explain such dysfunction in terms of olfactory sensitivity and cognition. These questions were studied by comparing HD patients and controls (matched for age, gender, and education) on absolute detection, intensity discrimination, quality discrimination, short-term recognition memory, and lexical- and picture-based identification for odor. Taste or vision were used as comparison modalities. The results suggest that whereas odor-recognition memory is not affected in patients with HD, these patients have impaired olfactory functioning with respect to absolute detection, intensity discrimination, quality discrimination, and identification. The three latter impairments were significantly explained by poor detection sensitivity. Odor identification was the function most affected.

Adult↗

PubMed1995

Odor identification as an early marker for Alzheimer's disease: impact of lexical functioning and detection sensitivity.

The impact of lexical functioning and detection sensitivity on the deficit of odor identification in Alzheimer's disease (AD) was studied in persons diagnosed with probable and questionable AD. Tests consisted of lexical-based odor identification, lexical-based picture identification, picture-based odor identification, and odor-detection threshold. Results suggest (1) that odor identification is poorer than picture identification in probable and questionable AD, (2) that odor identification continues to be poor even when lexical demands are eliminated, (3) that odor detection does contribute to the odor-identification deficit, but does not account for it completely, and (4) that odor identification tests have a correct classification rate of 83-100%. Odor identification tests can be very useful tools in diagnosing AD and should be considered an important addition to existing diagnostic test batteries.

Aged↗

PubMed1995

Reliability and validity of electrogustometry and its application to young and elderly persons.

Electrogustometric-threshold assessment demonstrated excellent test-retest reliability, good bilateral correspondence and age-related differences. Tactile and stimulus-related descriptors of the sensation elicited at detection threshold, as well as a lack of correlation between whole-mouth chemical thresholds and anterior tongue electrogustometric thresholds, raise questions for future research.

Adult↗

PubMed1995

Unawareness of smell loss in normal aging and Alzheimer's disease: discrepancy between self-reported and diagnosed smell sensitivity.

Awareness of loss in smell sensitivity was assessed in 80 normal elderly subjects, 80 patients with probable Alzheimer's disease (AD), and 80 patients with sinusitis by comparing measured smell sensitivity to questionnaire-based, self-reported sensitivity. Both AD patients and sinusitis patients had significantly poorer diagnosed smell sensitivity than the normal elderly. Both patient groups had thresholds which on average were about nine times more concentrated than those of the normal elderly. However, 74% of the AD patients and 77% of the normal elderly with smell loss reported normal smell sensitivity. In contrast, only 8% of the sinusitis patients with loss reported normal smell sensitivity.

Adolescent↗

PubMed1994

Olfactory-evoked potentials: assessment of young and elderly, and comparison to psychophysical threshold.

Olfactory-evoked potentials (OEPs) were recorded monopolarly at the Fz, Cz and Pz electrode sites in young adults and elderly subjects with an amyl acetate stimulus presented olfactometrically. Psychophysical odor thresholds for amyl acetate were determined using a two-alternative, forced-choice detection procedure. These demonstrated a decreased odor detection sensitivity in the elderly relative to tye young subjects. In accordance with the threshold findings, elderly subjects produced significantly smaller N1 and P2 amplitudes, and a trend towards longer latencies than younger subjects. Moreover, odor threshold was found to correlate with amplitude magnitude. The OEP findings, which are discussed in the context of previous OEP studies, offer promise as an objective, non-invasive measure of sensory function in both clinical and non-clinical settings.

Adult↗

PubMed1994

Context effects, reliability, and internal consistency of intermodal joint scaling.

Context effects, intraindividual variability, and internal consistency of intermodal joint scaling with magnitude estimation ("magnitude matching") were studied by instructing 12 subjects to judge the three pairs of odor intensity, loudness, and brightness on a common scale of perceived intensity as well as to judge odor intensity separately (unimodal magnitude estimation). Significant context effects were found by comparing odor intensity judgments obtained by separate versus intermodal joint scaling as well as across different modalities (loudness vs. brightness) in joint scaling. But no such effects were found for loudness or brightness when compared across modality of joint scaling. Intraindividual variability in the estimates imply about equal reliability in intermodal joint scaling and separate scaling. Good internal consistency was found, indicating that subjects are successful in expressing perceived intensities of different modalities on a common scale.

Acoustic Stimulation↗

PubMed1992

Environmentally induced changes in sensory sensitivities.

For studying changes in the sensory sensitivities, psychophysical methods offer a variety of models. The psychophysical approach also holds for applications on indoor air quality. The human senses can be used for characterizing environments in terms of effects on health and comfort, and have been used by the WHO for determining recommended exposure limits. The use of psychophysical methods for air pollution applications is illustrated by two studies on effects on sensory functions in smokers and passive smokers. Olfactory as well as auditory effects were found. Furthermore, methodological findings are presented, such as obtaining information on detectability and perceived intensity in the very same estimation procedure. The results also demonstrate the need for calibrating scales with regard to individual scaling behavior in perceived intensity measurements as well as the capability of the master scale principle for performing such a calibration.

Air Pollution, Indoor↗

PubMed1986