Use and efficacy of dry-mouth interventions in Sjögren's disease patients and possible association with perceived oral dryness and patients' discomfort.

OBJECTIVES: Sjögren's disease (SjD) patients use various interventions to relief their oral dryness. However, the use and efficacy of these interventions have only partially been evaluated. The present study aims to investigate whether there is an association between the perceived oral dryness and discomfort of SjD patients and their use of specific interventions. MATERIALS AND METHODS: A cross-sectional study was performed among SjD patients, who completed several questionnaires to assess the severity of their oral dryness and an inventory of dry-mouth interventions. The perceived efficacy of each intervention was reported on a 5-point Likert-scale. RESULTS: The questionnaires were returned by 92 SjD patients. For relief of oral dryness, they mostly used "eating fruit", "drinking tea", "moistening the lips", "drinking water, and "drinking small volumes" (> 50%). Three interventions had a frequency of use ranging from 2-6 times/day, whereas, "drinking water" and "drinking small volumes" showed higher frequencies (> 14). The highest overall efficacy (≥ 3.5) was reported for "chewing gum" and "using a mouth gel". Furthermore, various dry-mouth interventions showed significant associations with oral dryness scores and/or patients' discomfort. For example, "drinking small volumes" and "using XyliMelts" were associated with the Bother Index score. CONCLUSION: Great variation was found in the use of dry-mouth interventions by the participants and the severity of the oral dryness and/or patients' discomfort seemed to affect their choice of intervention. Notably, the mostly used interventions did not show the highest reported efficacy. CLINICAL RELEVANCE: These findings might help SjD patients and clinicians in their choice of effective dry-mouth interventions.

Subtyping cognitive profiles in Autism Spectrum Disorder using a Functional Random Forest algorithm.

DSM-5 Autism Spectrum Disorder (ASD) comprises a set of neurodevelopmental disorders characterized by deficits in social communication and interaction and repetitive behaviors or restricted interests, and may both affect and be affected by multiple cognitive mechanisms. This study attempts to identify and characterize cognitive subtypes within the ASD population using our Functional Random Forest (FRF) machine learning classification model. This model trained a traditional random forest model on measures from seven tasks that reflect multiple levels of information processing. 47 ASD diagnosed and 58 typically developing (TD) children between the ages of 9 and 13 participated in this study. Our RF model was 72.7% accurate, with 80.7% specificity and 63.1% sensitivity. Using the random forest model, the FRF then measures the proximity of each subject to every other subject, generating a distance matrix between participants. This matrix is then used in a community detection algorithm to identify subgroups within the ASD and TD groups, and revealed 3 ASD and 4 TD putative subgroups with unique behavioral profiles. We then examined differences in functional brain systems between diagnostic groups and putative subgroups using resting-state functional connectivity magnetic resonance imaging (rsfcMRI). Chi-square tests revealed a significantly greater number of between group differences (p < .05) within the cingulo-opercular, visual, and default systems as well as differences in inter-system connections in the somato-motor, dorsal attention, and subcortical systems. Many of these differences were primarily driven by specific subgroups suggesting that our method could potentially parse the variation in brain mechanisms affected by ASD.

Suprasegmental and segmental timing models in Mandarin Chinese and American English.

This paper formalizes and tests two key assumptions of the concept of suprasegmental timing: segmental independence and suprasegmental mediation. Segmental independence holds that the duration of a suprasegmental unit such as a syllable or foot is only minimally dependent on its segments. Suprasegmental mediation states that the duration of a segment is determined by the duration of its suprasegmental unit and its identity, but not directly by the specific prosodic context responsible for suprasegmental unit duration. Both assumptions are made by various versions of the isochrony hypothesis [I. Lehiste, J. Phonetics 5, 253-263 (1977)], and by the syllable timing hypothesis [W. Campbell, Speech Commun. 9, 57-62 (1990)]. The validity of these assumptions was studied using the syllable as suprasegmental unit in American English and Mandarin Chinese. To avoid unnatural timing patterns that might be induced when reading carrier phrase material, meaningful, nonrepetitive sentences were used with a wide range of lengths. Segmental independence was tested by measuring how the average duration of a syllable in a fixed prosodic context depends on its segmental composition. A strong association was found; in many cases the increase in average syllabic duration when one segment was substituted for another (e.g., bin versus pin) was the same as the difference in average duration between the two segments (i.e., [b] versus [p]). Thus, the [i] and [n] were not compressed to make room for the longer [p], which is inconsistent with segmental independence. Syllabic mediation was tested by measuring which locations in a syllable are most strongly affected by various contextual factors, including phrasal position, within-word position, tone, and lexical stress. Systematic differences were found between these factors in terms of the intrasyllabic locus of maximal effect. These and earlier results obtained by van Son and van Santen [R. J. J. H van Son and J. P. H. van Santen, "Modeling the interaction between factors affecting consonant duration," Proceedings Eurospeech-97, 1997, pp. 319-322] showing a three-way interaction between consonantal identity (coronals vs labials), within-word position of the syllable, and stress of surrounding vowels, imply that segmental duration cannot be predicted by compressing or elongating segments to fit into a predetermined syllabic time interval. In conclusion, while there is little doubt that suprasegmental units play important predictive and explanatory roles as phonological units, the concept of suprasegmental timing is less promising.

Repetition effects in word and pseudoword identification: comment on Salasoo, Shiffrin, and Feustel.

Two recent articles by Feustel, Shiffrin, and Salasoo (1983) and Salasoo, Shiffrin, and Feustel (1985) argue that word identification is based on episodic memory as well as semantic (or "permanent, abstract") memory. The earlier article argued for separate processing stages affected by repetition (episodic memory) and lexicality (semantic memory). To account for the new finding that number of repetitions interacts with lexicality, the later article invokes the same two types of memory, operating in parallel rather than serially. We argue that Salasoo et al.'s data are compatible with a wide variety of competing theories, including some that do not involve episodic memory at all. We question the relevance of a complex formal model shown by the authors to account for the main trends in the data, because it makes little use of key properties of episodic memory. Furthermore, we show that two variants of a less complex model inspired by logogen theory fit the data as well or better than the model of Salasoo et al., using fewer free parameters. We argue that what is needed is not an existence proof that one particular complex model can fit a body of data, but experimental manipulations that successfully discriminate between broad classes of competing theories.

Elaborated Reichardt detectors.

The elaborated Reichardt detector (ERD) proposed by van Santen and Sperling [J. Opt. Soc. Am. A 1, 451 (1984)], based on Reichardt's motion detector [Z. Naturforsch. Teil B 12, 447 (1957)], is an opponent system of two mirror-image subunits. Each subunit receives inputs from two spatiotemporal filters (receptive fields), multiplies the filter outputs, and temporally integrates the product. Subunit outputs are algebraically subtracted to yield ERD output. ERD's can correctly indicate direction of motion of drifting sine waves of any spatial and temporal frequency. Here we prove that with a careful choice of either temporal or spatial filters, the subunits can themselves become quite similar or equivalent to the whole ERD; with suitably chosen filters, the ERD is equivalent to an elaborated version of a motion detector proposed by Watson and Ahumada [NASA Tech. Memo. 84352 (1983)]; and for every choice of filters, the ERD is fully equivalent to the detector proposed by Adelson and Bergen [J. Opt. Soc. Am. A 2, 284-299 (1985)]. Some equivalences between the motion detection (in x, t) by ERD's and spatial pattern detection (in x, y) are demonstrated. The responses of the ERD and its variants to drifting sinusoidal gratings, to other sinusoidally modulated stimuli (on-off gratings, counterphase flicker), and to combinations of sinusoids are derived and compared with data. ERD responses to two-frame motion displays are derived, and several new experimental predictions are tested experimentally.(ABSTRACT TRUNCATED AT 250 WORDS)

Three theories of stroboscopic motion detection.

The three theories derive from three different paradigms. Suprathreshold judgements of perceived quality of motion in multi-flash displays are modelled by space-time Fourier analysis of the motion stimulus. Stroboscopic motion is perceived as being different from real motion to the extent that the additional Fourier components in stroboscopic motion are detectable. Stroboscopic motion of dots along conflicting paths leads to perceptual competition. The theory to describe perceptual I solution derives and proves the uniqueness of strength functions computed only from the time and from the distance between successive points on each path. Time-strength and motion-strength add to determine path-strength; only the strongest path is perceived. Motion-direction detection in continuously drifting two-flash combinations of sinusoidal gratings is described by elaborated Reichardt detectors (ERDs) that compute the covariance of temporal events in two adjacent locations. Other apparently different, detectors that account for direction-detection data are shown to be equivalent to ERDs.

Temporal covariance model of human motion perception.

We propose a model of direction-sensitive units in human vision. It is a modified and elaborated version of a model by Reichardt [Z. Naturforsch . Teil B 12, 447 (1957)]. The model is applied to threshold experiments in which subjects view adjacent vertical bars with independently (typically sinusoidally), temporally modulated luminances. The subject must report whether the patterns moved to the left or to the right. According to the model, a basic motion-detecting unit consists of two subunits tuned to opposite directions. Each performs a spatial and temporal linear filtering of its input; outputs of the filters are multiplied, and the multiplied output is integrated (for a time that is long relative to the modulation period). The model's output consists of the difference between the subunit outputs. Direction of movement is indicated by the sign of the model output. Mathematical analysis of the model yielded several predictions that were confirmed experimentally. Specifically, we found that (1) performance with complex patterns can be predicted by spatiotemporal Fourier analysis that results in the segregation and linear addition in the output for different temporal frequencies; (2) under special conditions, performance depends on the product of adjacent bar amplitudes, offering strong support for the multiplication principle; (3) performance is unaffected by addition of stationary patterns; and (4) addition of homogeneous flicker normally produces no effect but under special conditions reverses perceived direction. These and other results confirm our model and reject several other models, including Reichardt 's original model.

Length effects in word perception: we is better than i but worse than you or them.

Under tachistoscopic viewing conditions letters are better reported if they are presented as part of a word than if they are presented in isolation. Several recent theories attribute this word advantage to the influence of lexical representations. The present study replicated Wheeler's finding that the words I and A do not have the same advantage as other words, despite their lexical status. This result holds even under conditions designed to influence subjects to process I and A as words. The poor performance on these single-letter words was shown to be a manifestation of a more general length effect: Recognition of briefly presented words improves with increasing length (up to three or four letters). The perceptual advantage for longer words was not found for closely matched strings of unrelated letters. The strength and robustness of the word-length effect suggest that theories of the word advantage must include mechanisms that are length dependent.