Impact of tracheoesophageal puncture prosthesis airway resistance on in-vivo phonatory performance

Substantial differences have been established among in-vitro airway resistance properties of tracheoesophageal (TE) puncture prostheses (Weinberg & Moon, 1984). In this report, the impact of these in-vitro differences on the actual, in-vivo process of TE voice production is made explicit. Variation in in-vitro airway resistance among TE puncture prostheses is shown to exert substantial effects upon in-vivo phonatory mechanism opposition to flow, aerodynamic power required to initiate and sustain TE voice production, and TE phonatory efficiency. Individuals responsible for defining TE puncture options for laryngectomized patients are encouraged to consider these effects in clinical practice.

When Danny said no! Refusal of treatment by a patient of questionable competence

The patient we call Danny was a mildly mentally retarded male in his mid-thirties who adamantly refused kidney dialysis when it was offered as the only therapeutic option for his progressive kidney failure. It was uncertain how fully Danny understood the implications of his refusal. To complicate the case still further, several "advocates" emerged to speak on Danny's behalf--each with a somewhat different interpretation of the situation and different sets of value presuppositions and ethical principles to apply to the choice. We chronicle the development of this situation through a series of scenes; and in each scene we also attempt to clarify the ethical and medico-legal issues involved at that point. Danny was finally permitted to make this decision for himself--though more by default than by an agreement by all parties to honor his autonomy. Our hope is that this presentation will lead to further discussion and clarification of these important issues.

Reflex responses of the human jaw-closing system depend on the locus of intraoral mechanical stimulation

Innocuous mechanical stimuli were applied to eight sites on the tongue dorsum and palate while subjects used feedback to maintain a constant isometric biting force. Reflex responses of the jaw-closing system were measured as changes in force and in EMGs recorded from right and left masseter muscles. Stimulation at each of the eight sites produced reflex force and EMG responses in most subjects tested. The nature of the reflex responses strongly depended on the site of stimulation. Stimulation of the palate tended to produce suppression of ongoing EMG activity and decreases in background biting force. In contrast, stimulation of sites on the tongue posterior to the tip, most often resulted in excitatory EMG responses and increases in jaw-closing force. Unilateral, early excitatory responses were observed in the right masseter with stimulation of the right side of the tongue. The existence of spatially organized responses of the human jaw-closing system to innocuous intraoral stimulation is not consistent with the view that these cutaneous reflexes are primarily of protective significance.

Two simplified methods for estimating velopharyngeal orifice area

Two simplified methods for obtaining estimates of the area of the velopharyngeal orifice using nasal airflow and orifice differential pressure measures are described. In these methods, orifice areas are estimated by merely coordinating points on a graph or by interpolating values from a table. The accuracy of orifice area estimation by these methods compares favorably with estimation by other currently used methods. These simplified methods were developed to enlarge the application of hydraulic techniques by practicing clinicians.

The effects of increased nasal airway resistance on modeled velopharyngeal orifice area estimation

Research has shown that cleft lip and palate individuals have higher nasal airway resistance than normal subjects (Warren, Duany, and Fischer, 1969). The present work examined the predictive nature of modeled velopharyngeal orifice area calculations obtained using the hydrokinetic equation (Warren and DuBois, 1964) under conditions simulating increased degrees of nasal obstruction. The results of this project suggested that Warren's hydrokinetic method can be used to obtain accurate estimates of velopharyngeal orifice area under conditions of increased nasal airway resistance when airflow rates are nonvariant.

Evaluations of Blom-Singer tracheoesophageal puncture prostheses performance

Empirical and theoretical approaches to the assessment of Blom-Singer tracheoesophageal puncture prosthesis performance are described in this paper. The results of empirical studies provide new insights about the behavior of Blom-Singer devices. Namely, the overall average resistance (about 126 cm H2O/LPS) of these devices stems from two major factors: air entrance and air exit effects. The magnitudes of airway resistance for each of these factors and the relative contribution each factor makes to the total airway resistance of these prostheses are delineated. The performance of these devices and modifications thereof are shown to be characterized and predicted quite well using a one-dimensional, spring-constant mathematical model.

Passive eustachian tube opening pressure. Its measurement, normal values, and clinical implications

To measure passive eustachian tube opening pressure (PETOP) we have developed a pressure recording instrument that is activated by the sudden fall in output voltage of a sensitive acoustic impedance meter that occurs at the moment of transnasal insufflation of the middle ear. The PETOP was measured in 112 normal subjects aged 2 to 40 years. Normal values rose significantly throughout childhood and stabilized in early adolescence. When sequential insufflations were performed in the same subject, the PETOP fell, even though middle ear pressures had completely returned to baseline values before succeeding measurements were taken. Falls were enhanced by sequential swallowing. Our observations may be explained by the activity of surfactants in the eustachian tube. Measurement of PETOP may provide a more direct means of studying eustachian tube function than that provided by tympanometry alone.

Ocular findings in thoracic-pelvic-phalangeal dystrophy

Two unrelated patients with thoracic-pelvic-phalangeal dystrophy syndrome had retinal degeneration. A pathologic study of both eyes from one of the patients showed severe degeneration of the peripheral retina, with predominantly cone-type cells remaining.

Orthotopic homotransplantation of the human liver

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