The association between laryngopharyngeal sensory deficits, pharyngeal motor function, and the prevalence of aspiration with thin liquids.

OBJECTIVE: The study goal was to evaluate the association among laryngopharyngeal sensory deficits, pharyngeal motor function, and the prevalence of aspiration with thin liquids. STUDY DESIGN AND SETTING: We conducted a prospective study of 204 consecutive patients undergoing flexible endoscopic evaluation of swallowing with sensory testing and an assessment of pharyngeal motor function (pharyngeal squeeze). Patients were divided into 6 groups depending on the results of sensory and motor testing in the laryngopharynx. Subjects were given 5 mL of thin liquid, and the prevalence of aspiration in each group was compared. RESULTS: The mean age of the entire cohort was 65 years (58% female). The prevalence of aspiration in patients with intact laryngopharyngeal sensation was 2% (3 of 137) in persons with intact pharyngeal motor function and 29% (2 of 7) when pharyngeal motor function was impaired (P < 0.05). The prevalence of aspiration in patients with a moderate decrease in laryngopharyngeal sensation was 0% (0 of 9) in persons with intact pharyngeal motor function and 67% (2 of 3) when pharyngeal motor function was impaired (P < 0.05). The prevalence of aspiration in patients with severely diminished or absent laryngopharyngeal sensation was 15% (5 of 33) in persons with intact pharyngeal motor function and 100% (15 of 15) when pharyngeal motor function was impaired (P < 0.05). CONCLUSION: Patients with severely diminished laryngopharyngeal sensation and pharyngeal motor function are at an extremely high risk of aspirating thin liquids (100%). Moderate sensory deficits only appear to influence the prevalence of thin liquid aspiration in the presence of pharyngeal motor dysfunction. Severe laryngopharyngeal sensory deficits are associated with the aspiration of thin liquids regardless of the integrity of pharyngeal motor function. We assume that all persons with an insensate laryngopharynx aspirate thin liquids until proved otherwise. These results emphasize the relationship between laryngopharyngeal sensation and pharyngeal motor function in the evaluation of patients for suspected aspiration.     

Neonatal stroke: Clinical characteristics and cerebral blood flow velocity measurements

The clinical courses of 8 term infants with focal cerebral infarction or neonatal stroke were studied to determine whether such infants can be identified by current markers of perinatal distress, and whether changes in cerebral blood flow velocity (CBFV) occur during the acute phase of the disease. CBFV was measured from the middle cerebral artery (MCA) and anterior cerebral artery (ACA) utilizing duplex Doppler. Seven of the 8 patients required no resuscitation in the delivery room; 1 infant required brief bag and mask ventilation. No infant had evidence of severe fetal acidemia (i.e., cord pH <7). All 8 infants were initially admitted to the newborn nursery. Infants were identified on the basis of abnormal clinical findings observed during the first 48 hours: seizures (n = 6) and hypotonia and apnea (n = 2). Serum electrolytes, calcium, magnesium, and glucose levels were normal, and the sepsis evaluation including a spinal tap was sterile in all patients. Neuroimaging revealed nonhemorrhagic left focal MCA infarction (n = 6) and right focal MCA infarction (n = 2). Duplex Doppler demonstrated transient ipsilateral decreases in CBFV as compared to the contralateral unaffected side at clinical presentation in 4 infants. In 2 of these infants the decrease in CBFV involved both the MCA and ACA, and in 2 infants, only the MCA vessels. These side-to-side differences were not present at subsequent CBFV measurements. The data indicate that infants who develop neonatal stroke cannot be distinguished from infants who do not develop the lesion by current markers of perinatal distress. Because neonatal stroke frequently occurs as an unanticipated event, prevention may not be possible.     

Cone-rod dysfunction in patients with unexplained reduction in visual acuity

Electrophysiologic tests were performed in 233 patients who complained of reduced visual acuity with no satisfactory clinical explanation. The functional integrity of the retina was assessed from the light-and dark-adapted electroretinogram., Macular function and conduction in the optic nerves were estimated from the flash visual evoked potentials. Of the 233 patients 78 were grouped together on the basis of the electrophysiologic and clinical findings. They were characterized by subnormal electroretinogram responses with the cone system more affected than the rod system. The flash visual evoked potential responses were of abnormal waveform and prolonged implicit times. Most of these patients exhibited normal fundi. The reduction in visual acuity, the degree of electroretinogram deficits and the pattern of the visual evoked potential responses were similar in both eyes of each, patient, indicating a symmetric disorder. Slight deterioration of visual acuity and electrophysiologic variables were observed in 37 of the patients who were followed up over a period of up to 8 years. The electrophysiologic findings indicate that about 20% of patients complaining of unexplained reduction in visual acuity were suffering from a diffuse retinal disorder affecting the peripheral retina as well as the macular region. On the basis of electrophysiologic findings and clinical symptoms, we suggest grouping these patients under a new entity: cone-rod dysfunction.     

Marijuana Use among Calgary Youths as a Function of Sampling and Locus of Control

The findings reported in this paper were based on a representative, city wide sample (N= 708) of Calgary youths (aged 15–24). Twenty six per cent of the respondents reported having used marijuana “in the past six months”. Contrary to Smart's (1970) differential school drop out hypothesis, no decline in drug use was reported by 17 and 18 year old students, As measured by Rotter's concept, internally oriented respondents were less apt than externals to use marijuana. As predicted, this correlation was stronger among high school than college respondents. Several other demographic correlates of marijuana use were found.     

Development of an in vitro technique for measuring elastic properties of vocal fold tissue

The purpose of this investigation was to develop an in vitro technique for measurement of elastic properties of isolated vocal fold tissue. Larynges were excised from anesthetized dogs, immediately submerged in a Krebs-Ringer solution, and aerated with 95% oxygen and 5% carbon dioxide. The tissue was maintained in the aerated electrolyte solution throughout the experiment. The vocalis muscle was carefully dissected, with attachments to the arytenoid and thyroid cartilages maintained. The preparation was then subjected to isometric (constant length) force-elongation measures, which were converted to stress-strain values. Stage I of the investigation identified the dog model with the least intrastudy variability relative to the age, sex, and breed of the research animal, as well as to the effects of curare. Stage II investigated the effects of different instrumentation, definitions of reference length, methods of elongation, and effects of electrical stimulation. Once the procedure had been refined, the effects of age and sex were retested. There was a significant interaction between sex and strain and between age and strain. The least variability was obtained with curarized tissue from one sex of young, mixed-breed dogs, where an arbitrary 1 gram of initial force was the criterion for establishing "zero" strain. Problems associated with determination of reference length and various approaches to this problem are discussed.