Spatio-temporal patterns of diarrhoeal mortality in Mexico.

Diarrhoeal mortality rates in Mexican children dramatically declined during the 1980s and 1990s, concomitant with a temporal shift in peak deaths from summer to autumn-winter. The spatial dynamics of these patterns have not previously been studied. We first describe the seasonal features of paediatric diarrhoeal mortality in Mexico as a whole, then across individual states. While no geographical gradients in the magnitude of diarrhoeal mortality rates have been detected in recent years, we identified a distinct spatial pattern in the timing of peak mortality rate. In the 1980s the summer peak mortality was earliest around Mexico's capital and later in states to the southeast and northwest. Our results suggest that the direction and timing of those annual waves are related to the mean monthly precipitation and mean daily temperature. This pattern has disintegrated in recent years as the summer peak has diminished.

Effects of varying temporal scale on spatial models of mortality patterns attributed to pediatric diarrhea.

Public health data is often highly aggregated in time and space. The consequences of temporal aggregation for modeling in support of policy decisions have largely been overlooked. We examine the effects of changing temporal scale on spatial regression models of pediatric diarrhea mortality patterns, mortality rates and mortality peak timing, in Mexico. We compare annual and decadal level univariate models that incorporate known risk factors. Based on normalized sums of squared differences we compare between annual and decadal coefficients for variables that were significant in decadal models. We observed that spurious relationships might be created through aggregating time scales; obscuring interannual variation and resulting in inflated model diagnostics. In fact, variable selection and coefficient values can vary with changing temporal aggregation. Some variables that were significant at the decadal level were not significant at the annual level. Implications of such aggregation should be part of risk communication to policy makers.

The development and validation of a dysphagia-specific quality-of-life questionnaire for patients with head and neck cancer: the M. D. Anderson dysphagia inventory.

OBJECTIVE: To design a reliable and validated self-administered questionnaire whose purpose is to assess dysphagia's effects on the quality of life (QOL) of patients with head and neck cancer. DESIGN: Cross-sectional survey study. METHODS: Focus groups were convened for questionnaire development and design. The M. D. Anderson Dysphagia Inventory (MDADI) included global, emotional, functional, and physical subscales. One hundred consecutive adult patients with a neoplasm of the upper aerodigestive tract who underwent evaluation by our Speech Pathology team completed the MDADI and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Speech pathologists completed the Performance Status Scale for each patient. Validity and reliability properties were calculated. Analysis of variance was used to assess how well the MDADI discriminated between groups of patients. RESULTS: The internal consistency reliability of the MDADI was calculated using the Cronbach alpha coefficient. The Cronbach alpha coefficients of the MDADI subscales ranged from 0.85 to 0.93. Test-retest reliability coefficients of the subscales ranged from 0.69 to 0.88. Spearman correlation coefficients between the MDADI subscales and the SF-36 subscales demonstrated construct validity. Patients with primary tumors of the oral cavity and oropharynx had significantly greater swallowing disability with an adverse impact on their QOL compared with patients with primary tumors of the larynx and hypopharynx (P<.001). Patients with a malignant lesion also had significantly greater disability than patients with a benign lesion (P<.001). CONCLUSIONS: The MDADI is the first validated and reliable self-administered questionnaire designed specifically for evaluating the impact of dysphagia on the QOL of patients with head and neck cancer. Standardized questionnaires that measure patients' QOL offer a means for demonstrating treatment impact and improving medical care. The development and validation of the MDADI and its use in prospective clinical trials allow for better understanding of the impact of treatment of head and neck cancer on swallowing and of swallowing difficulty on patients' QOL.

Experience with Barton button and peristomal breathing valve attachments for hands-free tracheoesophageal speech.

BACKGROUND: Tracheostoma breathing valves permit hands-free tracheoesophageal (TE) speech production; however, few laryngectomees routinely use them because of problems with attachment. METHODS: We retrospectively reviewed the charts of 45 TE speakers to determine the success rate and factors associated with successful breathing valve use based on attachment. All patients attempted to use a tracheostoma breathing valve with either a standard or customized peristomal housing, or a standard or customized Barton button. Device selection was based on inspection of the patient's neck and peristomal contour. Six to eight consecutive hours of attachment defined success. RESULTS: Overall, 9% of subjects succeeded with any peristomal attachment as compared to 68% with either a standard (57%) or customized (85%) Barton button. Smooth stomal contour, a contiguous stomal lip, and correct button length were important for successful Barton button use. CONCLUSIONS: Standard or customized Barton buttons offer excellent alternatives to peristomal housing attachments for hands-free TE speech in select patients.