MIDDLE EAR PRESSURE DEREGULATION IN CLEFT PALATE PATIENTS: FORM-FUNCTION CORRELATES Otitis media with effusion (OME) is recognized as nearly universal in the population of infants and children with cleft palate (CP) and is often associated with long-standing conductive and, perhaps, sensorineural hearing losses. Most evidence suggests that OME in CP patients is a complication of inefficient Eustachian tube function (ETF). Previous studies have tried to relate the poor ETF in CP children to its anatomical substrate in the hope of identifying surgically modifiable conditions to reduce CP morbidity by decreasing OME prevalence. To date, no effect of any reconstructive procedure on OME prevalence has been demonstrated. In one study, infant CP patients who had tympanostomy tubes inserted at 3 months of age as prophylaxis for OME were tested before and after repair of the soft palate at 18 months of age. In contrast to a documented 70% frequency of one measure of ETF inefficiency, tubal constriction, in older CP children and adolescents with tubes for persistent OME, the tests in the infants showed a 30% prevalence for that measure. From this, we hypothesized that tubal constriction is a prognostic marker for persistent OME into late childhood and early adolescence. Here, we plan to use our most complete tests to characterize ETF in CP infants enrolled at age 15-24 months and followed for 5 years by yearly collection of clinical data for the presence/absence of OME and repeat ETF testing. To obtain anatomical data on these enrollees, we will obtain basal and lateral cephalograms at age 36 months and perform MRI tests prepalatoplasty and then at 3 and 5 years on a subset of the enrolled children. We will use these data to test the hypotheses that the prevalence of OME at 5 years of age is greater in CP children assigned at 15-24 months to the constrictor group;anatomic measures related to ETF are different in those two groups, and ETF improves with advancing age in both groups. Using the MRI data, sophisticated functional modeling will be used to reconstruct the functional anatomy of the ET system in groups of patients with different subtypes of CP and OME histories. Demonstration that tubal constriction is a prognostic marker of future OME experience would allow for defining an individual CP infant's need for close follow-up, frequent clinic visits and aggressive management of ME disease. Demonstration of a correspondence between ET structure and function would allow for diagnosing the underlying cause of the poor ETF in individual CP infants based on cephalometric data and possibly designing patient specific treatment plans that improve function and consequently prevent future OME episodes. The functional-anatomical reconstructions based on the MRI data will be studied for the mechanical interactions underlying the phenomenon of ET constriction in CP patients and examined for the possibility of surgical interventions to correct identified abnormal interactions.