Constrained emergence of universals and variation in syllable systems.

A computational model of emergent syllable systems is developed based on a set of functional constraints on syllable systems and the assumption that language structure emerges through cumulative change over time. The constraints were derived from general communicative factors as well as from the phonetic principles of perceptual distinctiveness and articulatory ease. Through evolutionary optimization, the model generated mock vocabularies optimized for the given constraints. Several simulations were run to understand how these constraints might define the emergence of universals and variation in complex sound systems. The predictions were that (1) CV syllables would be highly frequent in all vocabularies evolved under the constraints; (2) syllables with consonant clusters, consonant codas, and vowel onsets would occur much less frequently; (3) a relationship would exist between the number of syllable types in a vocabulary and the average word length in the vocabulary; (4) different syllable types would emerge according to, what we termed, an iterative principle of syllable structure and their frequency would be directly related to their complexity; and (5) categorical differences would emerge between vocabularies evolved under the same constraints. Simulation results confirmed these predictions and provided novel insights into why regularities and differences may occur across languages. Specifically, the model suggested that both language universals and variation are consistent with a set of functional constraints that are fixed relative to one another. Language universals reflect underlying constraints on the system and language variation represents the many different and equally-good solutions to the unique problem defined by these constraints.

Oral mucosal lesions and HIV viral load in the Women's Interagency HIV Study (WIHS).

The prevalence of oral lesions was assessed in a five-center subset of the Women's Interagency HIV Study (WIHS) and correlated with other features of HIV disease. Oral examinations were performed by dental examiners on 729 women (577 HIV-positive and 152 HIV-negative) during baseline examination. Significant differences between the groups were found for the following oral lesions: pseudomembranous candidiasis, 6.1% and 2.0%, respectively; erythematous candidiasis, 6.41% and 0.7%, respectively; all oral candidiasis, pseudomembranous and/or erythematous, 13.7% and 3.3%, respectively. Hairy leukoplakia was observed in 6.1% of HIV-positive women. No significant differences were found for recurrent aphthous ulcers, herpes simplex lesions, or papillomas. Kaposi's sarcoma was seen in 0.5% of HIV-positive and 0% of HIV-negative women. Using multiple logistic regression models controlling for use of antiretrovirals and antifungals, in HIV-positive women the presence of oral candidiasis was associated with a CD4 count <200 cells/microl, cigarette smoking, and heroin/methadone use; the presence of hairy leukoplakia was not related to CD4 count but was associated with high viral load. Oral candidiasis and hairy leukoplakia are confirmed as being common features of HIV infection in women and appear to be associated with HIV viral load, immunosuppression, and various other behaviorally determined variables.

The prevalence of xerostomia and salivary gland hypofunction in a cohort of HIV-positive and at-risk women.

The association of xerostomia and salivary gland hypofunction with HIV infection has been established for men but not for women. We investigated the prevalence of these conditions in a national cohort (n = 733) of HIV-positive and at-risk HIV-negative women. Participants in this prospective cross-sectional study were recruited from the Women's Interagency HIV Study (WIHS) at five outpatient USA clinics. Xerostomia was assessed based on "yes" responses to a dry-mouth questionnaire. Samples of unstimulated whole and chewing-stimulated whole saliva were collected under standardized conditions. The major salivary glands were also evaluated clinically. The prevalence of dry-mouth complaint, the absence of saliva upon palpation, and zero unstimulated whole saliva (flow rate = 0 mL/min) were significantly (p = 0.001) higher in HIV-positive women. Adjusted odds of zero unstimulated whole saliva were significantly (p = 0.02) higher in HIV-positive women vs. HIV-negative women (OR = 2.86; 95% CI, 1.23 to 6.63). Significant (p = 0.03) univariate association was found between zero unstimulated whole saliva and CD4 counts. Adjusted odds of zero unstimulated whole saliva were significantly (p = 0.02) higher for HIV-positive women with CD4 < 200 compared with those with CD4 > 500 (OR = 2.61; 95% CI, 1.17 to 5.85). Chewing-stimulated flow rates were not significantly different between seropositive and seronegative women. The prevalence of xerostomia and salivary gland hypofunction appears to be significantly higher in HIV-positive women relative to a comparable group of at-risk seronegative women. Immunosuppression levels measured by CD4 cell counts are significantly associated with xerostomia and salivary gland hypofunction in a population of HIV-positive women.

Salivary gland disease in human immunodeficiency virus-positive women from the WIHS study. Women's Interagency HIV Study.

OBJECTIVE: To determine the prevalence of enlargement, tenderness, and absence of saliva on palpation as indicators of salivary gland disease in women who are human immunodeficiency virus (HIV)-positive. STUDY DESIGN: The study subjects are participants in the Women's Interagency HIV Study (WIHS), a multicenter study examining HIV-seropositive women and at-risk HIV-seronegative women. A total of 576 HIV-positive women and 152 HIV-negative women were examined at their baseline oral visit for clinical markers of salivary gland disease. Viral load levels, CD4 counts, and CD8 counts were obtained as part of the related core study. RESULTS: HIV-positive women had higher rates of salivary gland enlargement (4.3%), tenderness (6.9%), and absence of saliva on palpation (26.6%) compared with HIV-negative women, who had rates of 1.3%, 4.6%, and 13.2%, respectively. Absence of saliva was significantly different (P =. 001) between the 2 groups. When 2 of the 3 clinical findings were combined, comparisons between the HIV-positive women and HIV-negative women became significant at the P <.05 level for every combination, except for enlargement/tenderness for the submandibular/sublingual gland. For the HIV-positive women, the viral load was significantly related to enlargement (P =.019) and enlargement/absence of saliva on palpation (P =.037) for the parotids and enlargement (P =.046), absence of saliva (P =.043), and enlargement/absence of saliva (P =.022) for the submandibular/sublingual glands. Significant linear trends were found for increasing viral load and enlargement (P =.013) and enlargement/tenderness (P =.024) for the submandibular/sublingual glands. Significance was present for submandibular/sublingual absence of saliva and tenderness/absence of saliva for CD4 and CD8 medians. CONCLUSIONS: Serostatus is related to salivary gland disease as assessed by glandular enlargement, tenderness, and absence of saliva on palpation. Furthermore, our findings indicate that a multidimensional approach to gland assessment may provide a more complete and perhaps more adequate description of glandular involvement with HIV infection.

The relative perceptual distinctiveness of initial and final consonants in CVC syllables.

Among the world's languages, syllable inventories allowing only initial consonants predominate over those allowing both initial and final consonants. Final consonants may be disfavored because they are less easy to identify and/or more difficult to produce than initial consonants. In this study, two perceptual confusion experiments were conducted in which subjects identified naturally produced consonant-vowel-consonant syllables in different frame sentences. Results indicated that initial consonants were significantly more identifiable than final consonants across all conditions. Acoustic analyses of the test syllables indicated that the relative identifiability of initial and final consonants might be explained in terms of production differences as indicated by the greater acoustic distinctiveness of initial consonants.

A prospective study of the use of liquid oral dietary supplements in nursing homes.

OBJECTIVE: To investigate the use of liquid oral dietary supplements among nursing home residents who were eating poorly and losing weight. DESIGN: A prospective, descriptive, anthropological study. SETTING: Two proprietary nursing homes with 105 and 138 beds. PARTICIPANTS: Purposive sampling was used to select 40 residents from among the 100 residents who were not eating well. Dietary data were collected on this sub-sample of 40 residents. MEASUREMENTS: Participant observation, in-depth interviews, event analysis, bedside dysphagia screenings, oral health examinations, body weight, body mass index (BMI), and chart review were used to collect data. Dietary data were collected over a 3-day period, and data were gathered on how supplements were ordered, served, and consumed. RESULTS: Supplements had been ordered for 29 of the subsample of 40 residents. Only nine of 29 residents were served the correct number and type of supplements as ordered by their physicians, and only two residents consumed the full amount of supplement as ordered. The overall mean percentage of supplement consumed compared with that ordered was 55.1%. Although supplements were ordered primarily to prevent weight loss and to facilitate weight gain, nearly half (n = 14) of the residents continued to lose weight. Supplements were ordered without investigating the underlying factors contributing to weight loss, such as inadequate staffing and lack of supervision at mealtime, undiagnosed dysphagia, and poor oral health. Without evaluation of these factors, it is unknown which residents might benefit from oral supplements. CONCLUSION: Findings indicate that supplements were used nonspecifically as an intervention for weight loss in nursing home residents without regard to dose, diagnosis and management of underlying problem(s), amount of supplement consumed, and outcome. Further research is needed to establish when supplements should be ordered, how to ensure that they will be taken, and whether they are effective.

Dentist-patient interactions in treatment decision-making: a qualitative study.

The growing involvement of patients, third party payers, and government in the financing, planning, and delivery of health services has heightened the demand for knowledge about the process of rendering care. This study used a qualitative methodology to examine dentist-patient interactions in treatment decision-making. A series of focus groups was conducted with dentists and patients participating in an ongoing investigation of dental treatment planning conducted at the University of North Carolina. Study findings indicate that dentist-patient interactions play an important role in treatment decision-making and that both are predicated on a variety of non-clinical factors. Dentists' intuition and judgment seem to be used not only to select desired health outcomes and the means for achieving them, but also to depart from the ideal and/or to modify treatment plan presentation on a patient-to-patient basis. Patients' impressions of dentists' examination styles, personalities, and ability to relate to them as individuals seem to mediate both treatment acceptance and willingness to participate in the decision-making process. Results of this investigation suggest that any effort aimed at improving dental treatment decision-making needs to acknowledge the interplay of clinical and psychosocial factors.

Production constraints on utterance-final consonant characteristics in babbling.

In order to evaluate hypotheses regarding production constraints on final consonants in babbling, 721 utterance-final consonants produced by 6 infants in consonant-vowel-consonant (CVC) syllables were examined and compared with the preceding consonant in the CVC. Consistent with earlier studies, major patterns were observed for each of the three main consonantal properties--place and manner of articulation and voicing. These patterns included a strong tendency for final consonants to repeat the place of articulation of nonfinal consonants and a tendency for relatively more fricative, nasal and voiceless consonants to occur in final position than in nonfinal position. The high frequency with which final consonants shared place of articulation with the preceding consonant was considered to reflect 'frame dominance' or the tendency of a relatively constant mandibular cycle (the frame) to determine the structure of utterances with very little contribution from other active articulators. The manner and voicing effects were attributed to an overall terminal energy decrease in the vocal production system.

Strategies for conducting dental examinations among cognitively impaired nursing home residents.

Many nursing home residents have poor oral health and are in need of treatment. A major barrier to providing care is the difficulty of examining cognitively impaired elders. In two research studies, 625 exams were conducted on 181 nursing home residents, the majority of whom suffered severe cognitive impairment. Qualitative data collected during the course of these two studies revealed strategies that permitted examiners to conduct the examinations successfully, including developing rapport with the residents, providing a quiet environment, and enlisting the help of the primary caregiver. The importance of interdisciplinary collaboration among health professionals, especially dentists and nurses, is discussed.

Selected restoration and tooth conditions: United States, 1988-1991.

The DMF index provides one source of information on past and present dental caries experience; however, important limitations hinder its ability to characterize fully the impact of dental caries. The purpose of this paper is to describe a measure of selected restoration and tooth conditions that supplements information from the DMF index and to report on the application of this measure as part of the Third National Health and Nutrition Examination Survey, Phase 1, conducted between 1988 and 1991. Data from this survey were used to estimate the prevalence and severity of selected disaggregated physical and biological oral conditions among dentate adults aged 18 to 74 years. Trained, standardized, and calibrated dentist examiners assessed 28 permanent teeth or tooth spaces for each of 6,767 subjects. Teeth or tooth spaces were classified based on criteria for: defective intracoronal restorations, crowns, or bridges; gross loss of tooth structure associated with a restoration; pulpal involvement; or retained roots. Approximately 40.5%, or 61.6 million, dentate adults had at least one tooth or tooth space that met the criteria. Among all persons, an average of 0.9 teeth or tooth spaces met the criteria for at least one category. Adults with at least one scored tooth or tooth space had an average of 2.2 such teeth or tooth spaces. Data from this assessment supplement information available from the DMF index to provide a broader profile of the impact of dental caries on permanent teeth of US adults.

Denture use and the technical quality of dental prostheses among persons 18-74 years of age: United States, 1988-1991.

For persons without all or some of their natural teeth in one or both arches, the use of a complete or partial denture and the quality of the denture used are important aspects of their oral health and functioning. This report of prosthodontic findings from the first three years of the 1988-94 National Health and Nutrition Examination Survey (NHANES III-Phase 1) provides estimates of denture use among the US civilian non-institutionalized population 18-74 years of age, as well as seminal information on the technical quality of dental prostheses nationwide. NHANES III-Phase 1 prosthodontic findings indicated that about one in five persons 18-74 years of age wears a removable prosthodontic appliance of some type. Overall, removable prosthodontic appliances are worn disproportionately more often by women than by men, and less frequently by whites than by blacks. Comparisons among race-ethnicity categories indicate that Mexican-Americans are less likely to use dentures than either of their non-Hispanic counterparts. Analyses of prosthodontic evaluation data indicated that approximately 60% of denture users have at least one problem with a denture. These findings from the oral component of NHANES III-Phase 1 provide clear indications that, despite increasing trends in tooth retention, dependence on removable prosthodontic appliances is still a reality of life for millions of Americans.

Beyond pregnancy gingivitis: bringing a new focus to women's oral health.

The compromised functional status, physical confinement, medical conditions, and cognitive impairments of significant numbers of women have important implications for oral health risk and dental treatments. In addition, there are a variety of economic, social, psychological, and behavioral factors which are operative in placing women at high risk for development of oral diseases. This paper describes the available U.S. data on women's oral health and examines some of the biological, behavioral, and societal factors which may be important for a more comprehensive understanding of this subject. It is this broad array of factors which differentiate women from men and which should be considered when defining priority research and treatment issues for women's oral health.

Oral health and the quality of life.

The study of the impact of oral diseases and conditions on individuals and societies has been slow to develop but has made major progress during the 1980s. Not only did improvements in understanding oral quality of life require developing and using more social and behavioral outcome measures, it required reassessing clinical indices. Reports on oral quality of life to date are often based on investigations that originally had other purposes; consequently there is inconsistent evidence about the associations among oral health, general health, and quality of life. In fact, in much of the cited literature the evidence is equivocal. Yet, in more recent research designed specifically to investigate quality of life (Meei-Shia Chen, PhD, personal communication, 1991), it is evident that orofacial conditions, diseases, and pain can be disruptive and can have considerable impacts at both the individual and societal levels in terms of reduction in normal activities; conversely, medical and social conditions can affect oral health. It is notable that across studies there is an incongruence between health care professional and patient assessments of quality of life--they view the issues differently. Although oral diseases are very prevalent, the early symptoms are often not severe, leading many individuals to disregard them, or if acknowledged, to define them as normal or unimportant. This may reflect a form of fatalism, i.e., their oral health is as good as could be expected. It is necessary to assess oral health and quality of life over time. Individuals indicating satisfaction or dissatisfaction with appearance, function, and self-esteem at one point in time are doing so against a framework of immediate or long-term expectations. In regard to specific procedures, such as surgery or dentures, it is necessary to know what the individual expects if the health care professional is to provide improvements in perceived and actual quality of life. Similarly, it is difficult to provide meaningful interpretation of self-assessed physical and social functioning and appearance against clinical measures, if the level of earlier dysfunction is not known. For example, in the case of full denture wearers, the evidence might be interpreted to suggest that these individuals have excellent oral quality of life. Without taking into account the extent of physical and social dysfunction and poor appearance prior to the dentures, and the consequent improvement against this base, it is impossible to evaluate and consequently improve quality of life. Understanding this process requires longitudinal studies.(ABSTRACT TRUNCATED AT 400 WORDS)

The role of autopecking in behavioral contrast.

Four groups of four pigeons each were studied on two different multiple schedules. The cues correlated with the schedule components were localized on the response key for two groups and were not localized for the others. Two groups worked on multiple schedules with variable interval 15-sec in both components, and variable interval 15-sec in one component and extinction in the other. The other two groups had identical procedures except that food was presented on a response-independent variable-time schedule. Variable-interval birds with localized stimuli showed marked behavioral contrast; variable-interval birds with non-localized stimuli showed no behavioral contrast. Variable-time birds with key-light stimuli acquired high rates of autopecking, which changed as treatment changed in a manner that paralleled rate changes, resulting in behavioral contrast for variable-interval birds. Variable-time birds with non-localized stimuli key pecked only at a low rate. The findings indicate that behavioral contrast in pigeons may result from the autopecking that is obtained with stimulus-contingent food presentation.