Swallowing disorders in the elderly

Functional and morphological evidence of age-related denervation in rat laryngeal muscles

Laryngeal muscle dysfunction compromises voice, swallowing, and airway protection in elderly adults. Laryngeal muscles and their motor neurons and their motor neurons communicate via the neuromuscular junction (NMJ). We tested the hypothesis that aging disrupts NMJ organization and function in the laryngeal thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles We determined NMJ density and size and acetylcholine receptor (AChR) subunit mRNAs in TA and PCA muscles from 6-, 18-, and 30- month old-rats. NMJ function was determined with tubocurarine (TC) and contractions during nerve and muscle stimulation. NMJ size, abundance, and clustering decreased in 30-month TA and PCA muscles. AChRe mTNA and protein increased with age in both muscles. AChRg mRNA increased with age in both muscles while protein content increased in TA only. Aging PCA and TA were more sensitive to TC, demonstrating functional evidence of denervation. These results demonstrate that NMJs become smaller and less abundant in aging TA and PCA muscles.

Current concepts in the anatomy and origin of pharyngeal diverticula

The role of this paper is to present the current concepts in anatomy and etiopathogenesis of pharyngeal diverticula. Precise anatomical considerations highly emphasizing the weak anatomic areas which predispose the pouch formation are discussed. Focus exposed in details will also be given upon the structural and functional characteristics of the upper esophageal sphincter as well as to its physiological states, architecture and dynamic functions. A brief review of hystorical and current perspectives regarding the origin of pharyngeal diverticula has also been given. Special attention is given to the abnormal cricopharyngeal function in patients with pharyngeal pouches in the terms of altered UES compliance, importance of gastroesophageal reflux and histopathologic changes of cricopharyngeal muscle.

The effects of aging on hypoglossal motoneurons in rats

Aging can result in a loss of neuronal cell bodies and a decrease in neuronal size in some regions of the brain and spinal cord. Motoneuron loss in the spinal cord is thought to contribute to the progressive decline in muscle mass and strength that occurs with age (sarcopenia). Swallowing disorders represent a large clinical problem in elderly persons; however, age-related alterations in cranial motoneurons that innervate muscles involved in swallowing have been understudied. We aimed to determine if age-related alterations occurred in the hypoglossal nucleus in the brainstem. If present, these changes might help explain alterations at the neuromuscular junction and changes in the contractile properties of tongue muscle that have been reported in older rats. We hypothesized that with increasing age there would be a loss of motoneurons and a reduction in neuronal size and the number of primary dendrites associated with each hypoglossal motoneuron. Neurons in the hypoglossal nucleus were visualized with the neuronal marker NeuN in young (9-10 months), middle-aged (24-25 months), and old (32-33 months) male F344/BN rats. Hypoglossal motoneurons were retrograde-labeled with injections of Cholera Toxin beta into the genioglossus muscle of the tongue and visualized using immunocytochemistry. Results indicated that the number of primary dendrites of hypoglossal motoneurons decreased significantly with age, while no age-associated changes were found in the number or size of hypoglossal motoneurons. Loss of primary dendrites could reduce the number of synaptic inputs and thereby impair function.

Effect of aging on blood flow in rat larynx

OBJECTIVE/HYPOTHESIS

Age-associated muscular changes and fatigue have been shown to affect phonatory function. Reductions in blood flow with aging could translate to reductions in oxidative capacity within laryngeal muscles and increased fatigability. We tested the hypothesis that there would be increased capillary red blood cell (RBC) velocity and a reduction of capillary density in the thyroarytenoid (TA) muscle of senescent rats.

STUDY DESIGN/METHODS

Ten male Fisher 344/Brown Norway rats in two age groups were used: young adult (9 mo) and old (28-30 mo). Sixteen additional young and old rats were used in a fluorescent microsphere experiment that examined blood flow rates before and after a surgical manipulation. With use of a specially equipped intravital microscope, in vivo measurements of capillary geometry and flow were obtained, including RBC velocity, capillary density, tortuosity, and number of branch points.

RESULTS

There was an age-related reduction in capillary surface area as evidenced by reduced lineal density of capillaries. In addition, reduced RBC transit time was suggested by the reduction in branch points found with age. There was no change in RBC velocity with aging. The surgical method used to expose the TA muscle for blood flow recordings did not significantly affect resultant blood flow measurements.

CONCLUSIONS

We developed a method to evaluate in vivo laryngeal microvasculature. We found age-related changes in microvascular geometry within the TA muscle of the rat that could affect blood flow to this critical muscle of phonation and airway protection. These microvascular changes could contribute to age-related laryngeal dysfunction.

Clinical and scintigraphic assessment of swallowing of older patients admitted to a tertiary care geriatric ward

This study aimed to verify if older patients admitted to a tertiary care geriatric ward with no spontaneous complaints of dysphagia have impaired swallowing function as detected by a specialized clinical assessment and a scintigraphic study of swallowing. Thirty patients (mean age = 76.2 years, 17 women), consecutively admitted for the treatment of acute or chronic diseases, were studied. Two control groups were also studied, one consisting of 10 healthy older persons (mean age = 69.6 years, 5 women) and the other consisting of 20 young volunteers (mean age = 25.4 years, 11 women). A complete clinical assessment of swallowing was performed by a speech pathologist. Each subject was also submitted to scintigraphic studies of oropharyngeal transit after swallowing liquid and syrup boluses labeled with 99m technetium phytate. Transit time, clearance time, and residuals were measured. Five patients had impairments in swallowing function detected by clinical assessment, three of them in the absence of complaints even after specific questioning. Scintigraphic transit times did not differ between the groups studied; however, residuals after syrup swallows were greater in the patient group compared with the healthy older volunteers. These findings suggest an increased risk for aspiration and the usefulness of a brief assessment of swallowing function in all patients admitted to tertiary care geriatric wards.

The impact of aging on eating, drinking, and swallowing function in people with Down's syndrome

Many people with Down's syndrome (DS) experience eating, drinking, and swallowing (EDS) difficulties, which can potentially lead to life-threatening conditions such as malnutrition, dehydration, and aspiration pneumonia. As the life expectancy of people with DS continues to improve, there is an increasing need to examine how the aging process may further affect these conditions. Published research studies have yet to address this issue; therefore, this article draws on the literature in three associated areas in order to consider the dysphagic problems that might develop in aging people with DS. The areas examined are EDS development in children and adolescents with DS, EDS changes associated with aging, and EDS changes associated with dementia of the Alzheimer's type (DAT) because this condition is prevalent in older adults with DS. This article concludes that unlike in the general population, the aging process is likely to cause dysphagic difficulties in people with DS as they get older. Therefore, it is suggested that longitudinal studies are needed to examine the specific aspects of EDS function that may be affected by aging and concomitant conditions in DS.

Prevalence of perceived dysphagia and quality-of-life impairment in a geriatric population

Dysphagia is an important problem for the elderly. While well characterized in acutely ill populations, the prevalence and quality-of-life changes associated with dysphagia remain poorly defined in the community geriatric population. This study recruited individuals 65 years and older from an independent-living facility. Two validated questionnaires were used: the M.D. Anderson Dysphagia Inventory (MDADI) and the general health Short Form-12 survey (SF-12v2). Each participant also answered two questions: "Do you have difficulties with swallowing?" and "Do you think that swallowing difficulties are a natural part of aging?" Fifteen percent of subjects reported difficulties with swallowing. Of these, over half suffered substantial quality-of-life impairment in one or more domains of the MDADI. With respect to the second question, 23.4% of subjects believed dysphagia to be a normal part of aging, 37.4% did not. The SF-12v2 only weakly correlated with the MDADI in this population. In conclusion, there is a relatively high prevalence of dysphagia in the community-based geriatric population; significant quality-of-life impairment is a frequent finding. General health measures do not appear to be sensitive to swallowing-related quality of life. Finally, individuals may inaccurately ascribe swallowing problems to normal aging, supporting the role of community education about dysphagia in the elderly.

Antipsychotic drug use and risk of pneumonia in elderly people

OBJECTIVES

To investigate the association between antipsychotic drug use and risk of pneumonia in elderly people.

DESIGN

A nested case-control analysis.

SETTING

Data were used from the PHARMO database, which collates information from community pharmacies and hospital discharge records.

PARTICIPANTS

A cohort of 22,944 elderly people with at least one antipsychotic prescription; 543 cases of hospital admission for pneumonia were identified. Cases were compared with four randomly selected controls matched on index date.

MEASUREMENTS

Antipsychotic drug use in the year before the index date was classified as current, recent, or past use. No prescription for an antipsychotic in the year before the index date was classified as no use. The strength of the association between use of antipsychotics and the development of pneumonia was estimated using multivariate logistic regression analysis and expressed as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Current use of antipsychotics was associated with an almost 60% increase in the risk of pneumonia (adjusted OR=1.6, 95% CI=1.3-2.1). The risk was highest during the first week after initiation of an antipsychotic (adjusted OR=4.5, 95% CI=2.8-7.3). Similar associations were found after exclusion of elderly people with a diagnosis of delirium. Current users of atypical agents showed a higher risk of pneumonia (adjusted OR=3.1, 95% CI=1.9-5.1) than users of conventional agents (adjusted OR=1.5, 95% CI=1.2-1.9). There was no clear dose-response relationship.

CONCLUSION

Use of antipsychotics in elderly people is associated with greater risk of pneumonia. This risk is highest shortly after the initiation of treatment, with the greatest increase in risk found for atypical antipsychotics.

Dysphagia following anterior cervical arthrodesis is associated with continuous, strong retraction of the esophagus

BACKGROUND

The prevalence of dysphagia after anterior cervical decompression and arthrodesis is estimated to be 50% within one month and 21% at twelve months. However, its exact etiology is not well understood. The objective of the present study was to explore the relationship between intraoperative intra-esophageal pressure due to surgical retraction, esophageal mucosal blood flow at the level of surgery, and postoperative dysphagia. Our hypothesis was that sustained elevated pressure on the esophagus during anterior cervical arthrodesis is associated with postoperative dysphagia.

METHODS

Seventeen selected patients scheduled for anterior cervical arthrodesis were studied. Throughout the procedure, intraluminal pressure in the upper esophageal sphincter was measured (mm Hg) with a custom-made manometer probe and mucosal perfusion was measured at the level of surgery with a laser Doppler flowmeter. The type of retraction chosen by the surgeon was noted. Postoperatively, the patients were specifically evaluated for dysphagia on the first postoperative day and at six weeks, three months, and six months postoperatively with use of the M.D. Anderson Dysphagia Inventory.

RESULTS

Four of the eleven patients who had dynamic retraction and five of the six patients who had static retraction during surgery had postoperative dysphagia. In the group of patients with dysphagia, the average M.D. Anderson Dysphagia Inventory score decreased from 93.8 +/- 12.1 preoperatively to 67.7 +/- 11.4 on the first postoperative day (p < 0.001). The patients with dysphagia had a significantly higher average intraluminal pressure (60.8 +/- 54.3 compared with 54.4 +/- 51.8 mm Hg; p < 0.0001) as well as significantly lower average mucosal perfusion (26.1 +/- 18.1 compared with 40.8 +/- 26.2 tissue perfusion units; p < 0.0001) in comparison with the asymptomatic patients.

CONCLUSIONS

Patients with dysphagia following anterior cervical arthrodesis were exposed to higher intraoperative esophageal pressure and decreased esophageal mucosal blood flow during surgical retraction as compared with patients without dysphagia. In this small series, dynamic retraction seemed to be associated with a lower prevalence of postoperative dysphagia.

Dysphagia in the elderly: preliminary evidence of prevalence, risk factors, and socioemotional effects

OBJECTIVES

Epidemiological studies of dysphagia in the elderly are rare. A non-treatment-seeking, elderly cohort was surveyed to provide preliminary evidence regarding the prevalence, risks, and socioemotional effects of swallowing disorders.

METHODS

Using a prospective, cross-sectional survey design, we interviewed 117 seniors living independently in Utah and Kentucky (39 men and 78 women; mean age, 76.1 years; SD, 8.5 years; range, 65 to 94 years) regarding 4 primary areas related to swallowing disorders: lifetime and current prevalence, symptoms and signs, risk and protective factors, and socioemotional consequences.

RESULTS

The lifetime prevalence of a swallowing disorder was 38%, and 33% of the participants reported a current problem. Most seniors with dysphagia described a sudden onset with chronic problems that had persisted for at least 4 weeks. Stepwise logistic regression identified 3 primary symptoms uniquely associated with a history of swallowing disorders: taking a longer time to eat (odds ratio [OR], 9.5; 95% confidence interval [CI], 2.3 to 40.2); coughing, throat clearing, or choking before, during, or after eating (OR, 3.4; 95% CI, 1.1 to 10.2); and a sensation of food stuck in the throat (OR, 5.2; 95% CI, 1.8 to 10.0). Stroke (p = .02), esophageal reflux (p = .003), chronic obstructive pulmonary disease (p = .05), and chronic pain (p = .03) were medical conditions associated with a history of dysphagia. Furthermore, dysphagia produced numerous adverse socioemotional effects.

CONCLUSIONS

This study provides preliminary evidence to suggest that chronic swallowing disorders are common among the elderly, and highlights the need for larger epidemiological studies of these disorders.

Rehabilitative management of oropharyngeal dysphagia in acute care settings: data from a large Italian teaching hospital

A high incidence of oropharyngeal dysphagia (OD) in acute-care settings has been reported; however, no data on its management are found in the literature. Here we report the experience with rehabilitative management of OD in a large Italian hospital. The characteristics of inpatients with OD during 2004 have been studied prospectively. For each patient, demographic data, the department referring the patient, the disease causing OD, and the presence of a communication disorder were registered. The swallowing level at the beginning and at the end of rehabilitation were recorded. Of the 35,590 inpatients admitted to San Giovanni Battista Hospital of Turin during 2004, 222 of them were referred for the assessment and rehabilitation of OD. The inpatients with OD came from different departments and mainly had a neurologic disease. In 110 patients a communication disorder was present. The swallowing impairment was moderate to severe at the moment of referral, while on average patients were able to eat by mouth after swallowing therapy. Dysphagia rehabilitation in an acute care setting is requested from different departments because of its prevalence and severity; skilled specialists are needed for early assessment and the best management.

Effect of aging on tongue protrusion forces in rats

The purpose of this study was to ascertain the effect of aging on muscle contractile properties associated with tongue protrusion in a rat model. Fischer 344/Brown Norway hybrid rats, ten young (9 months old) and ten old (32 months old), were used to measure protrusive contractile properties. Results showed a significant reduction in tetanic forces in the old animals. The following measures of muscle contraction were not different between age groups: mean twitch contraction force, twitch contraction time, twitch contraction half-decay time, and a calculated measure of fatigability. In conclusion, aging influenced protrusive tongue muscle contractions in a rat model such that tetanic forces were reduced. The reduction of tetanus force may parallel findings in human subjects relative to isometric tongue force generation and may be associated with age-related disorders of swallowing.

Dysphagia: implications for older people

This review opens with an outline definition of dysphagia, its causes, and why it is vital that people involved in the health care of older people should be aware of it. A brief consideration of prevalence is followed by an overview of assessment options. We conclude with a section on management.

Myosin heavy chain-based fiber types in the adult human cricopharyngeus muscle

The cricopharyngeus (CP) muscle is a major component of the upper sphincter of the esophagus. Its physiology is complex; a variety of reflexes maintain CP sustained contraction except during swallowing, when it relaxes to allow a food bolus to pass into the esophagus. In order to understand CP function, we previously studied the normal adult human CP and found that it has an unusual layered structure, with a slow inner and fast outer layer. In addition, a majority of its muscle fibers express unusual myosin heavy chain (MHC) isoforms (slow-tonic, alpha-cardiac, neonatal, and embryonic) as well as the major MHC isoforms (types I, IIa, and IIx). In this study, autopsied adult human CP muscles were studied with immunocytochemical techniques to determine the patterns of MHC coexpression in CP muscle fibers. The results show that CP fibers were hybrids expressing from two to six MHC isoforms. Ten different combinations of MHC isoforms were identified in CP fibers, with the most common (54%) containing three MHC isoforms. The variety of hybrid CP fiber types suggests that the CP is capable of a wide range of contraction characteristics. Determination of MHC expression patterns of the CP muscle fibers is critical for evaluating the contractile properties of the sphincter.

Discoordination of laryngeal and respiratory movements in aged rats

Voice and swallowing actions require the coordination of multiple motor systems, and this coordination may be impaired with aging. Although recent work has reported impairments in age-related laryngeal kinematics in rats, the temporal relationship of laryngeal excursions to the respiratory cycle is unknown. The goal of this study was to assess laryngeal-respiratory coordination by examining temporal interrelationships between change in laryngeal aperture and chest wall movement during quiet breathing in a rat model. Glottal images were recorded, digitized, and synchronized with respiratory signals, and temporal features were measured. In the young animals, glottal opening began before the onset of inspiration, and glottal and respiratory cycles were phasic and stereotypic. In old animals, however, inspiration often began during the glottal closing phase, and both respiratory signals were asymmetric. Discoordination of laryngeal and respiratory motor actions associated with aging may be caused by a generalized decline in sensorimotor cranial functions and may contribute to age-related swallowing and communication impairment.

Contractile dysfunction and altered metabolic profile of the aging rat thyroarytenoid muscle

The larynx and its muscles are important for ventilation, coughing, sneezing, swallowing, Valsalva's maneuver, and phonation. Because of their functional demands, the intrinsic laryngeal muscles have a unique phenotype: very small and fast fibers with high mitochondrial content. How aging affects their function is largely unknown. In this study, we tested the hypothesis that an intrinsic laryngeal muscle (thyroarytenoid muscle, a vocal fold adductor) would become weaker, slower, and fatigable with age. Muscles from Fischer 344 x Brown Norway F1 hybrid rats (6, 18, and 30 mo of age) were used for in vitro contractile function and histology. Thyroarytenoid muscles generated significantly lower twitch and tetanic forces at 30 mo vs. 6 and 18 mo. Maximal shortening velocity decreased by 20% at 30 mo (vs. 6 mo), and velocity of unloaded shortening was slower at 18 and 30 mo by 19 and 27% vs. 6 mo. There was no histochemical evidence of altered myosin ATPase activity at 18 or 30 mo of age. Fatigue resistance was significantly decreased at 18 and 30 mo. We also found abundant mitochondrial clusters and ragged red fibers in the muscles of 30-mo-old rats, and there was an age-related increase in glycogen-positive fibers. We conclude that rat thyroarytenoid muscles become weaker, slower, and more fatigable with age. These functional changes are not due to alterations in myosin ATPase activity, but a switch in the expression of myosin isoforms remains a possibility. Finally, the alterations in mitochondrial and glycogen content indicate a shift in the metabolic characteristics of these muscles with age.

Reabilitação vocal em pacientes com doença de Parkinson: fatores interferentes

TEMA: reabilitação vocal de pacientes com doença de Parkinson idiopática. OBJETIVO: descrever os fatores interferentes na reabilitação vocal de cinco indivíduos com doença de Parkinson e apresentar as modificações na comunicação oral. MÉTODO: foram realizadas entrevistas e avaliações pré e pós-tratamento vocal pelo método Lee SilvermanVoice Treatment (LSVT<FONT FACE=Symbol>Ò</FONT>) RESULTADOS: observou-se melhora na articulação, intensidade e qualidade vocais, gerando satisfação em pacientes e família. CONCLUSÃO: a análise dos fatores que contribuíram ou dificultaram o processo terapêutico aponta os aspectos que devem ser levados em consideração para atingir resultados eficazes.

Effect of deficits in laryngeal sensation on laryngeal muscle biochemistry

Swallowing deficits in elderly people are significant clinical problems and may be associated with impaired pharyngolaryngeal sensation. However, the extent to which sensory innervation affects the motor system is unclear. Our purpose was to examine differences in biochemical properties of laryngeal muscles following sensory nerve ablation. We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis to evaluate laryngeal muscles of young and old Fischer 344/Brown Norway rats, and rats that underwent sensory ablation via bilateral section of the superior laryngeal nerve, internal branch (SLNi), or mixed sensory-motor nerve ablation via left-sided recurrent laryngeal nerve (RLN) section. In lateral thyroarytenoid muscle, a reduction was found in the proportion of the most rapidly contracting myosin heavy chain isoform (type 2B) with SLNi section, RLN section, and aging. Section of the SLNi did not alter the proportion of any myosin heavy chain isoform within the lateral cricoarytenoid or posterior cricoarytenoid muscles, but RLN section resulted in a reduction in the proportion of type 2B. Accordingly, alteration in biochemical properties of the lateral thyroarytenoid muscle alone was demonstrated following sensory ablation. We conclude that sensory changes may affect properties of laryngeal muscles, and may thus have an impact on motor control during critical functions, such as airway protection during swallowing.

Salivary production in Parkinson's disease

Hypersialorrhea is a common phenomenon in Parkinson disease (PD). The objective of this study was to determine whether patients with PD had an abnormally increased production of saliva and whether the production of saliva could be associated to factors related to either the disease characteristics or to its treatment. A total of 83 patients with PD and 55 control subjects participated in this study. Because of the age difference between the two groups, comparisons were made on a +/-2-year age-matched sample of 44 PD patients and 44 control subjects. PD patients produced significantly less saliva than control subjects. Correlations were obtained with the 83 PD patients between unstimulated salivary flow and patients characteristics. When controlling for age, sex, and Hoehn and Yahr scale, decreased production of saliva correlated significantly with the dose of levodopa and the symptoms of xerostomia. When controlling for medications, there was no relationship between the production of saliva and the evolution of the disease. This study shows that patients with PD produce less saliva than normal. Factors influencing the production of saliva include the use of levodopa and female gender. Our results may have implications for the treatment of drooling in PD.

Age-Related Remodeling of the Hypopharyngeal Constrictor Muscle and Its Subneural Apparatuses: A Scanning Electron Microscopical Study in Rats

Age-related remodeling of the hypopharyngeal constrictor muscle was studied by comparing the morphological features of the subneural apparatus (SNA) of the thyropharyngeal (TP) and cricopha ryngeal (CP) muscles in young and old rats. Scanning electron microscopy revealed that the TP and CP muscles had both gutter- and depression-type SNAs, although different proportions of the two types of apparatus were found in each muscle. In young-adult rats, the gutter-type SNA was predominant in the TP muscle, whereas in the CP muscle the depression type was predominant. By contrast, in old rats, the depression-type SNA was predominant in the TP muscle, while no such transformation of the dominant SNA was noted in the CP muscle. In addition, the number of type IIb and type I muscle fibers was lower and greater, respectively, in older animals compared with those of younger animals. Furthermore, there were more type IIc fibers in the TP muscle of old rats, but no difference in the CP muscle between young and old animals. These findings suggest that the transformation of SNAs and the muscle fibers of the hypopharyngeal constrictor muscle takes place during aging and that their remodeling processes differ in the TP and CP muscles.

Neurophysiology of swallowing

Swallowing is a complex motor event that is difficult to investigate in man by neurophysiological experiments. For this reason, the characteristics of the brain stem pathways have been studied in experimental animals. However, the sequential and orderly activation of the swallowing muscles with the monitoring of the laryngeal excursion can be recorded during deglutition. Although influenced by the sensory and cortical inputs, the sequential muscle activation does not alter from the perioral muscles caudally to the cricopharyngeal sphincter muscle. This is one evidence for the existence of the central pattern generator for human swallowing. The brain stem swallowing network includes the nucleus tractus solitarius and nucleus ambiguus with the reticular formation linking synaptically to cranial motoneuron pools bilaterally. Under normal function, the brain stem swallowing network receives descending inputs from the cerebral cortex. The cortex may trigger deglutition and modulate the brain stem sequential activity. The voluntarily initiated pharyngeal swallow involves several cortical and subcortical pathways. The interactions of regions above the brain stem and the brain stem swallowing network is, at present, not fully understood, particularly in humans. Functional neuroimaging methods were recently introduced into the human swallowing research. It has been shown that volitional swallowing is represented in the multiple cortical regions bilaterally but asymmetrically. Cortical organisation of swallowing can be continuously changed by the continual modulatory ascending sensory input with descending motor output.

SIGNIFICANCE

Dysphagia is a severe symptom complex that can be life threatening in a considerable number of patients. Three-fourths of oropharyngeal dysphagia is caused by neurological diseases. Thus, the responsibility of the clinical neurologist and neurophysiologist in the care for the dysphagic patients is twofold. First, we should be more acquainted with the physiology of swallowing and its disorders, in order to care for the dysphagic patients successfully. Second, we need to evaluate the dysphagic problems objectively using practical electromyography methods for the patients' management. Cortical and subcortical functional imaging studies are also important to accumulate more data in order to get more information and in turn to develop new and effective treatment strategies for dysphagic patients.

Cricopharyngeal spasm and Zenker's diverticulum

Cricopharyngeal spasm and Zenker's diverticulum represent disorders of the pharyngoesophageal junction for which a unifying theory of etiology has yet to be established. There is, however, a large body of evidence that supports an association with gastroesophageal reflux. Cricopharyngeal myotomy is the key to successful management of both disorders. Newer transoral endoscopic techniques of management have a lower overall morbidity than traditional open approaches in appropriately selected patients and are therefore gaining popularity as the preferred method of treatment.

Videofluoroscopic swallow studies in unilateral cricopharyngeal dysfunction

OBJECTIVES/HYPOTHESIS

Although the cricopharyngeus muscle is a ring-like structure, unilateral cricopharyngeal dysfunction can produce significant dysphagia. This entity has not been well described in the literature. The aims of the study were to identify the characteristic findings on videofluoroscopic swallow studies in patients with dysphagia secondary to unilateral cricopharyngeal dysfunction, to note the associated vagal nerve injury, and to evaluate patient outcomes following ipsilateral cricopharyngeal myotomy.

STUDY DESIGN

Retrospective clinical investigation.

METHODS

The clinic charts, electromyographic tests, videostroboscopic examinations, and videofluoroscopic swallow studies were reviewed from a series of patients who presented to our institution from 1993 to 2001 with dysphagia and findings on videofluoroscopic swallow studies suggestive of unilateral cricopharyngeal dysfunction on posterior-anterior view. In patients treated with ipsilateral cricopharyngeal myotomy, postoperative findings on swallow studies and patient outcomes were also reviewed.

RESULTS

Eighteen patients demonstrated findings characteristic of unilateral cricopharyngeal muscle dysfunction on videofluoroscopic swallow study. The common feature was a unilateral shelf-like barrier at the cricopharyngeus on the posterior-anterior view with pooling of liquid bolus in the ipsilateral pyriform sinus and episodic shunting to the contralateral side. Eight patients did not have evidence of cricopharyngeal dysfunction (ie, cricopharyngeal bar) on lateral films. Of the 18 patients, 14 had histories consistent with vagal injury secondary to trauma (n = 2), neoplastic involvement (n = 7), iatrogenic injury (n = 2), or central nervous system disease (n = 3). Results of videostroboscopic examinations demonstrated vocal fold motion impairment in 14 patients, and electromyographic test results confirmed unilateral vagal injuries in those who underwent electromyographic testing (n = 6). In the remaining 4 of 18 patients, videostroboscopic examinations demonstrated normal vocal fold abduction but impaired lengthening with a posterior glottic gap, and electromyographic test results (n = 4) indicated unilateral superior laryngeal nerve involvement. Of the 15 patients treated with ipsilateral cricopharyngeal myotomy, 1 patient required postoperative esophageal dilations for an esophageal stricture distal to the cricopharyngeus, whereas the remaining 14 patients had functional resolution of their dysphagia.

CONCLUSION

In patients presenting with dysphagia and evidence of unilateral vagal injury, careful assessment of posterior-anterior view on videofluoroscopic swallow study should be included to evaluate for unilateral cricopharyngeal dysfunction.

Pharmacokinetic comparison of fast-disintegrating and conventional tablet formulations of risperidone in healthy volunteers

BACKGROUND

Difficulties with and resistance to tablet-taking are common in all patient groups and can exacerbate compliance problems and undermine treatment efficacy. In recent years, rapidly dissolving oral drug formulations have been developed to overcome problems related to swallowing difficulties.

OBJECTIVE

The goal of this study was to evaluate the bioequivalence of a fast-disintegrating oral tablet of risperidone and the conventional oral tablet.

METHODS

This was a randomized, open-label, 2-way crossover trial in which healthy volunteers received two 0.5-mg tablets of a fast-disintegrating oral risperidone formulation and two 0.5-mg tablets of conventional oral risperidone, each in a single administration. Blood samples for pharmacokinetic analysis of the active moiety (risperidone + 9-hydroxy-risperidone), risperidone, and its active metabolite 9-hydroxy-risperidone were obtained during a 96-hour period after dosing. Safety assessments included monitoring of adverse events, hematology and biochemistry tests of the sampled blood, urinalysis, blood pressure measurements, and electrocardiography.

RESULTS

The bioequivalence assessment was based on pharmacokinetic and statistical analysis of data from 37 subjects who completed both treatment periods. The plasma concentration-time profiles of the active moiety, risperidone, and 9-hydroxy-risperidone were similar after intake of the 2 formulations. The fast-disintegrating tablet and the conventional tablet showed bioequivalence with respect to the active moiety, risperidone, and 9-hydroxy-risperidone. The 90% CIs for the mean treatment ratios of the log-transformed peak plasma concentration, area under the plasma concentration-time curve (AUC) to the last quantifiable time point, and AUC extrapolated to infinity were all within the predefined equivalence range from 80% to 125%. Twenty-eight of 50 (56%) subjects originally randomized reported adverse events, with a similar incidence for both treatments. All adverse events were mild, with somnolence and headache being the most frequently reported. No clinically relevant changes were observed in physical, biochemical, hematologic, or urinalysis variables during the study.

CONCLUSION

In this study in healthy subjects, a single administration of two 0.5-mg fast-disintegrating risperidone tablets was bioequivalent to a single administration of two 0.5-mg conventional risperidone tablets.