Comments on Selected Recent Dysphagia Literature

David W. Buchholz, MD and Stefanie Neumann, MA

Bolus Aggregation in the Oropharynx Does Not De-pend on GravityPalmer, JBArch Phys Med Rehabil 79:691–696, 1998

Hiiemae, Palmer, and others described a “processmodel” of mammalian feeding [1–3] that differs from theconventional swallowing model used almost universallyamong those of us involved in dysphagia in humans.Among the major differences between the process modeland the conventional model are that in the process model(a) food is propelled through the faucial pillars into theoropharynx while chewing continues and (b) the bolus,rather than being formed in the oral cavity, accumulatesin the oropharynx (including the valleculae) for up toseveral or more seconds before the pharyngeal swallowensues. Findings that would be considered pathologicaccording to the conventional model—findings such as“premature leakage” and “delayed swallowing reflex”—are physiologic in the process model.

In the present study, Palmer hypothesized thattransport of chewed solid food from the oral cavity intothe oropharynx is driven actively by tongue–palate con-tact and does not depend on gravity. Five healthy sub-jects swallowed barium-impregnated soft and hard foodsfirst seated upright and then kneeling face down. Palm-er’s hypothesis was confirmed by the finding that, re-gardless of head position or initial food consistency,transport of chewed solid food from the oral cavity intothe oropharynx typically started several seconds beforeonset of the pharyngeal swallow. In addition, bolus ag-gregation in the valleculae began an average of 1.7 ± 2.5sec before the onset of the pharyngeal swallow.

Comments

By stepping back and looking at the process of feedingrather than isolating the act of swallowing from its natu-ral context as is routine in conventional swallowing stud-

ies, Palmer has helped redefine both normal and abnor-mal human swallowing. The implications of the processmodel are far reaching. What are we to make of the manypublished studies that have drawn conclusions based onthe conventional assumption that findings such as pre-mature leakage and delayed swallowing reflex are un-equivocally abnormal? At what point, if ever, are suchfindings abnormal? Perhaps most importantly, shouldswallowing study protocols, for clinical or research pur-poses or both, be modified to simulate more closely theprocess of feeding, or should we remain committed toexamining (and treating) the act of swallowing in anunnatural vacuum?

References

1. Hiiemae KM, Hayenga SM, Reese A: Patterns of tongue and jawmovement in a cinefluorographic study of feeding in the ma-caque.Arch Oral Biol 40:229–246, 1995

2. Palmer JB, Rudin NJ, Lara G, Crompton AW: Coordination ofmastication and swallowing.Dysphagia 7:187–200, 1992

3. Palmer JB, Hiiemae KM: Integration of oral and pharyngealbolus propulsion: a new model for the physiology of swallow-ing. Jpn J Dysphagia Rehabil 1:15–30, 1997

Pharyngeal Swallowing Disorders: Selection for andOutcome after MyotomyMason RJ, Bremner CG, DeMeester TR, Crookes PF,Peters JH, Hagen JA, DeMeester SRAnn Surg 228:598–608, 1998

Among 143 consecutive patients referred to a swallowclinic between 1991 and 1997 with symptoms suggestiveof a pharyngeal swallowing disorder, 36 were excludedbecause of Zenker’s diverticula, and the remaining 107patients (median age4 72 years) were evaluated withvideofluorography, pharyngoesophageal segment ma-nometry, and a standardized questionnaire. In 66 pa-

Dysphagia 14:184–187 (1999)

© Springer-Verlag New York Inc. 1999

tients, there was no identified underlying disease.Twenty had had strokes, six had received pharyngealirradiation, three had undergone resection of meningio-mas, three had parkinsonism, and single patients eachhad one of nine miscellaneous neurologic diagnoses.

Cricopharyngeal myotomy was offered to 46 pa-tients with severe symptoms and associated videofluoro-graphic findings and manometric evidence of outflowresistance. Thirty-one patients underwent myotomy;among the other 15 patients offered surgery, some re-fused and some did not receive insurance authorization.Postsurgical outcomes were graded as excellent (com-plete relief of all swallowing symptoms), good (minorsymptoms that did not require therapy), fair (minorsymptoms that required therapy), or poor (persistent orworsened symptoms). Postsurgical follow-up was for amedian of 12 months (range4 2–48 months).

No patient died within 30 days of surgery, and thepostsurgical morbidity rate was 16%. All 14 patientswith no identified underlying disease had excellent orgood outcomes. Five of eight (63%) poststroke patientsand 10 of 17 (59%) patients with other neurologic diag-noses had excellent or good outcomes. Seven of the 31patients (23%) who underwent myotomy had poor out-comes. Among eight patients receiving full or supple-mental gastrostomy feedings preoperatively, five (63%)had excellent or good outcomes, and gastrostomy wasdiscontinued subsequently in seven.

With regard to videofluorographic findings, ex-cellent or good outcomes were achieved in five of sixpatients (84%) with “pharyngeal dilatation” and in nineof 13 (69%) with pooling of contrast. Fourteen of 17patients (82%) with “a cricopharyngeal bar” and 12 of 17patients (71%) with laryngeal penetration and aspirationhad excellent or good outcomes.

Among manometric findings, 18 of 20 patients(90%) with “impaired opening” and 16 of 19 (84%) withelevated intrabolus pressure had excellent or good out-comes. The authors state, “At the multivariate level, onlytwo factors significantly predicted a successful outcome:no discernible cause for the dysphagia (odds ratio4 7.5;95% confidence level 1.1 to 49.3) and impaired sphincteropening (odds ratio4 8.4; 95% confidence level 0.9 to81).” Based on these data, only one factor—no discern-ible cause for the dysphagia—significantly predicted asuccessful outcome. Of five patients with normal mano-metric findings, only two did well after surgery.

Mason et al. conclude, “Our results with myoto-my were similar to those of other studies, which havereported that approximately two thirds of patients willbenefit.” They note that poor pharyngeal peak contrac-tion pressure did not predict poor outcome, and theyspeculate that the beneficial effect of myotomy on

sphincter opening is due at least in part to division of thehyoid depressor muscles (omohyoid and sternohyoid)leading to improved elevation of the larynx.

Comments

It is remarkable that 66 of the 107 patients studied and 14of the 31 patients who underwent surgery had no iden-tified neurologic or other basis for pharyngeal dysphagia.One wonders what, if any, neurologic investigation wasconducted.

This report adds to previous suggestions that my-otomy helps some patients with neurogenic dysphagiaand that appropriate selection criteria may include im-paired sphincter opening and increased intrabolus pres-sure but does not enable us to determine among indi-vidual patients to whom myotomy should be offered.

A Randomized, Controlled, Single-Blind Trial of Nu-tritional Supplementation after Acute StrokeGariballa SE, Parker SG, Taub N, Castleden CMJ Parenter Enteral Nutr 22:315–319, 1998

This study examined the feasibility of enteral sip feedingas an effective nutrition intervention after acute stroke.Forty-two acute ischemic stroke inpatients with impairednutritional status but without difficulty swallowingwithin 1 week after stroke were randomized to receiveeither regular hospital food or daily oral food supple-mentation for 4 weeks in addition to hospital food.

The group receiving oral nutritional supplemen-tation had significantly greater energy intake, protein in-take, and rises in serum albumin and iron concentrations.There was a trend to lower mortality at 3 months in thesupplemented group (two deaths, or 10%, vs. sevendeaths, or 35%, in the control group;p 4 0.127, relativerisk 4 0.29, 95% confidence interval4 0.07–1.21).

Gariballa et al. conclude that enteral sip feedingis effective in improving nutritional intake and nutri-tional status in stroke patients who do not have swallow-ing difficulties, and there may be some beneficial effecton clinical outcome, but larger studies are needed.

Comments

Several aspects of this investigation are commendable,especially its practicality and emphasis on the largelyneglected topic of poststroke malnutrition.

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Aspiration in Unilateral Recurrent Laryngeal NerveParalysis after SurgeryPerie S, Laccourreye O, Bou-Malhab F, Brasnu DAm J Otolaryngol 19:18–23, 1998

Perie et al. describe five patients with postoperative uni-lateral recurrent laryngeal nerve paralysis after head andneck or thoracic surgery. One patient had undergone totalthyroidectomy with right paratracheal lymph node dis-section for thyroid cancer, and four patients had under-gone left pneumonectomy with mediastinal lymph nodedissection for lung cancer. Postoperative symptoms in-cluded dysphonia in all patients and dysphagia in one.

These patients were studied with videofluorogra-phy and by fiberoptic laryngoscopy in association withmethylene blue dye testing. Three patients had no aspi-ration, one had silent aspiration, and one had symptom-atic aspiration. All were able to tolerate normal dietswithout complication.

Comments

As the authors discuss, it is not clear that these patientshad only unilateral recurrent laryngeal nerve injury; thepossibility of other intraoperative nerve injury cannot beexcluded. We remain dubious that isolated unilateral re-current laryngeal nerve dysfunction can result in symp-tomatic dysphagia and aspiration, and we suspect thatsuch reported cases are contaminated by additional im-pairment. We invite readers to enlighten us by means oftheir apt case reports to the contrary.

Serial Fiberoptic Endoscopic Swallowing Evaluationsin the Management of Patients with DysphagiaLeder SBArch Phys Med Rehabil 79:1264–1269, 1998

Leder describes 32 patients with a variety of underlyingdiseases who underwent serial fiberoptic endoscopicevaluation of swallowing (FEES) to help determinewhen to resume oral feeding and what bolus consisten-cies to use. Sixteen patients (50%) underwent FEESthree times, and 16 underwent FEES four to six times.The elapsed time from initial to final FEES was 6–293days, but in just under half of patients the mean intervalwas less than 2 weeks.

Final feeding recommendations based on serialFEES led to resumption of oral feeding in one form oranother in 22 of 32 patients (69%). No patient who re-sumed oral feeding was reported to suffer aspiration

pneumonia, although Leder does not specify the meansor duration of surveillance for this and other potentialcomplications of oral feeding.

Leder concludes, “This study has shown that se-rial FEES can provide efficient and safe dysphagia man-agement. . . . ”

Comments

Aside from our uncertainty as to how long-term safety oforal feeding was ascertained, we are puzzled as to howthis study informs us that FEES, serial or otherwise,leads to efficient dysphagia management. Without a con-trol group and without long-term follow-up of clinicaloutcomes, how do we know that the findings of FEES (orvideofluorography) do not encourage us to restrict thefeeding status of our patients unnecessarily? Why do weassume that the more we know about patients’ swallow-ing dysfunction, the more wisely we can manage it? Thatmakes sense, and it may be true, but it remains to bedemonstrated.

Kinetic Magnetic Resonance Imaging Analysis ofSwallowing: A New Approach to Pharyngeal Func-tionFoucart JM, Carpentier P, Pajoni D, Rabischong P, Phar-aboz CSurg Radiol Anat 20:53–55, 1998

This report details the use of turbo-FLASH magneticresonance imaging (MRI) to acquire five 10-mm sectionsper second and thereby analyze the oropharyngeal appa-ratus during swallowing.

Comments

Within a few years kinetic MRI may become a primarymethod of studying normal and abnormal swallowing. Itspotential advantages include superior resolution of softtissue details and the ability to perform three-dimen-sional analysis.

Magnetic Field Changes in the Human Brain Due toSwallowing or SpeakingBirn RM, Bandettini PA, Cox RW, Jesmanowicz A,Shaker RMagn Reson Med 40:55–60, 1998

186 D.W. Buchholz and S. Neumann: Recent Dysphagia Literature

Birn et al. applied functional MRI to evaluation of brainactivity during swallowing and speaking. The authorsaddress movement distortion artifact as it relates to thefinding of magnetic field perturbations in the inferiorregion of the brain during swallowing and speaking.

Comments

It is likely that MRI will be useful for the purpose ofimaging the oropharyngeal apparatus during swallowing(see above) before it becomes informative as to the de-tails of the neuroanatomy and neurophysiology of centralcontrol of swallowing.

Dysphagia in Patients with Inclusion Body MyositisHouser SM, Calabrese LH, Strome MLaryngoscope 108:1001–1005, 1998

The authors performed a retrospective study of medicalrecords and self-reported follow-up survey of 22 patientswith biopsy-proven inclusion body myositis (IBM). Con-trary to previous reports indicating a 40% incidence ofdysphagia in IBM [1–3], Houser et al. found 80% to havedysphagia. Progressive dysphagia indicated poor prog-nosis. Two patients with IBM and dysphagia who weretreated with cricopharyngeal myotomy “experiencedmarked improvement in their swallowing function.”

Comments

The most common myopathy in patients older than 50years is IBM, and this report of the high incidence ofdysphagia in IBM underscores the importance of consid-ering IBM in the differential diagnosis of gradually pro-gressive pharyngeal dysphagia. Unfortunately, IBM isusually refractive to immunosuppressive therapy, and therole of myotomy remains unclear.

References

1. Verma A, Bradley WG, Adesina AM, Sofferman R, PendleburyWW: Inclusion body myositis with cricopharyngeus muscle in-volvement and severe dysphagia.Muscle Nerve 14:470–473, 1991

2. Darrow DH, Hoffman HT, Barnes GJ, Wiley CA: Managementof dysphagia in inclusion body myositis.Arch Otolaryngol HeadNeck Surg 118:813–817, 1992

3. Letz BP, Engel AG, Nishino H, Stevens JC, Litchey WJ: Inclu-sion body myositis: observation in 40 patients.Brain119:727–747, 1989

Aphagia Due to Pharyngeal Constrictor Paresis fromAcute Lateral Medullary InfarctionVigderman AM, Chavin JM, Kososky C, Tahmoush AJJ Neurol Sci 155:208–210, 1998

Vigderman et al. report on a patient with MRI-provenunilateral lateral medullary infarction resulting in apha-gia due to severe bilateral pharyngeal paresis. The au-thors conclude “that, in man, the bilateral medullaryswallowing centers function as one integrated center, andthat infarction of a portion of this center is sufficient tocause complete loss of swallowing.”

Comments

This report is consistent with previous studies indicatingthat (a) unilateral lateral medullary infarction can causebilateral pharyngeal paresis and (b) each medullary swal-lowing center has essential control of both sides of thepharynx [1,2].

References

1. Neumann S, Buchholz D, Wuttge-Hannig A, Hannig C, ProsiegelM, Schroter-Morasch H: Bilateral pharyngeal dysfunction after lat-eral medullary infarction [abstract].Dysphagia 9:263, 1994

2. Neumann S, Buchholz D, Jones B, Palmer J: Pharyngeal dys-function after lateral medullary infarction is bilateral: review of15 additional cases [abstract].Dysphagia 10:136, 1995

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