Comments on Selected Recent Dysphagia Literature

David W. Buchholz, MD and Stefanie Neumann, MA

This is our final appearance as editors of this section. We are stepping down to pursue other personal and professionalinterests and to make room for new voices to be heard. It has been an honor and a pleasure to give life to Comments,and we look forward to witnessing the further development of our offspring from adolescence to a more advanced levelof maturation. Thanks for indulging us with your readership.

Functional Units, Chewing, Swallowing, and FoodAvoidance Among the ElderlyHildebrandt GH, Dominguez BL, Schork MA, LoescheWJJ Prosthet Dent 77:588–595, 1997

In this study of 602 elderly subjects, the number of teethwas compared with the number and types (natural vs.prosthetic) of dental functional units (opposing toothpairs) to correlate the number of functional units withcomplaints about chewing and swallowing. The authorsnote that the number of teeth may overestimate mastica-tory potential because this value does not take into ac-count the functional arrangement of the teeth. A personcould have 14 teeth—none with opposing occlusal con-tacts—and zero functional units or 14 teeth—each op-posed to another—creating seven functional units.

Reduced numbers of functional units were corre-lated with increased reports of difficulty in chewing andswallowing and with avoidance of stringy foods (includ-ing meat), crunchy foods (including vegetables), and drysolid foods (including breads). Removable prostheticteeth did not prevent these consequences and did notappear to have masticatory potential equivalent to naturalteeth.

Hildebrandt et al. conclude that emphasis shouldbe placed on maintaining natural teeth in functional pairsand that elective transition to prosthetic teeth should beavoided. Reduced numbers of functional units alsostrongly correlated with feeding dependence.

CommentsDespite different outcome measures, this report remindsus of the findings of Langmore et al. [1] regarding thenegative impact of dental loss on not only chewing but

also swallowing. Among the risk factors for aspirationpneumonia noted by Langmore et al. are both reducednumbers of teeth and dependent feeding status—the lat-ter being a consequence of reduced numbers of func-tional units in the study by Hildebrandt et al., suggestingdouble trouble as a result of dental loss.

The data of Hildebrandt et al. indicate that furtherstudies of the adverse effects of dental loss on chewingand swallowing should look beyond number of teeth andconsider functional units and type of teeth (natural vs.prosthetic). We wonder: if all of the time, effort, andexpenditure devoted to diagnosing and treating dyspha-gia were instead focused on optimal dental care, wouldthe ultimate outcome—the overall prevalence and con-sequences of feeding problems—be better or worse?

Reference

1. Langmore SE, Terpenning MS, Schork A, Chen Y, Murray JT,Lopatin D, Loesche WJ: Predictors of aspiration pneumonia:how important is dysphagia?Dysphagia 13:69–81, 1998

Radiological Evidence of Subclinical Dysphagia inMotor Neuron DiseaseBriani C, Marcon M, Ermani M, Costantini M, Bottin R,Iurilli V, Zaninotto G, Primon D, Feltrin G, Angelini CJ Neurol 245:211–216, 1998

Twenty-three patients with motor neuron disease(MND), 16 with complaints of dysphagia and sevenwithout, underwent videofluoroscopy, videopharyngo-laryngoscopy, and pharyngoesophageal manometry. Re-sults were analyzed (a) to define the pattern of swallow-ing in MND patients complaining of dysphagia, (b) to

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evaluate whether subclinical abnormalities could be de-tected, and (c) to assess the roles of these three diagnosticprocedures.

The findings were that (a) the oral phase wasmost compromised, followed by the pharyngeal phase,(b) all patients without dysphagia symptoms had video-fluoroscopic findings similar to those with symptoms,and (c) videofluoroscopy was more sensitive than theother two techniques in identifying abnormalities ofswallowing.

Regarding videopharyngolaryngoscopy, Briani etal. found that it was not sensitive in detecting swallowingabnormalities in patients with or without symptoms. Itshowed a normal pattern in seven of 15 symptomatic andsix of seven asymptomatic patients.

Briani et al. note that the pattern of videofluoro-scopic abnormalities “was not found in patients with oro-pharyngeal dysphagia owing to other neuromuscular dis-eases,” and they reference a publication on myotonicdystrophy by their group. Reviewing the manometricfindings, the authors emphasize that the main cause ofdysphagia in MND is oral phase defects and that only aminority of patients show upper esophageal sphincterdysfunction; therefore, only a minority might benefitfrom cricopharyngeal myotomy.

CommentsA shortcoming of this study is the lack of controls forvideofluoroscopy and videopharyngolaryngoscopy. Weare doubtful of the authors’ claim that the pattern ofvideofluoroscopic abnormalities in MND is specific tothe disease, and their reference cited in support of thisassertion is a study of only one other neuromuscularillness (myotonic dystrophy). Those issues aside, Brianiet al. have added to our knowledge of both clinical andsubclinical dysphagia in MND. Videofluoroscopy ap-pears more sensitive than videopharyngolaryngoscopyfor detection of dysphagia in MND, and this superiorityof videofluoroscopy is probably generalizable to othercauses of neurogenic dysphagia.

ACE Inhibitors and Symptomless Dysphagia [Letter]Arai T, Yasuda Y, Takaya T, Toshima S, Kashiki Y,Yoshimi N, Fujiwara HLancet 352:115–116, 1998

Arai et al. began with two premises: (a) elderly patientswith silent dysphagia have decreased cough reflexes and(b) angiotensin converting enzyme (ACE) inhibitors,used to treat hypertension, induce coughing. The authorsdo not mention it, but ACE inhibitors increase substance

P levels, and this may be why ACE inhibitors inducecoughing.

The authors studied an ACE inhibitor as treat-ment for silent poststroke dysphagia, including effect ofthe drug on low serum substance P concentrations. Thestudy group included 16 patients with hypertension andsilent poststroke dysphagia, 10 nondysphagic individualstaking an ACE inhibitor (imidapril hydrochloride) forhypertension, and seven healthy controls. Noting thatsilent poststroke dysphagia worsens during sleep, whenthe cough reflex is weakened, Arai et al. instilled 1 ml ofa radioactive tracer via a nasal catheter during sleep inthe group with silent poststroke dysphagia. Patients wereimaged the next morning. Patients were treated with im-idapril 5–10 mg daily, although the report does notclarify when they were treated in relation to being stud-ied, and serum substance P levels were measured beforeand 12 weeks after administration.

The patients with silent poststroke dysphagia hadlow serum substance P levels at baseline compared withthe nondysphagic hypertensive patients and the controlsubjects. After ACE inhibitor treatment, serum substanceP concentrations rose in eight of the 16 silent poststrokedysphagia patients and in 10 patients silent dysphagiaimproved, although the details are unreported. The au-thors conclude that ACE inhibitors may counteract silentdysphagia in poststroke patients.

CommentsThis brief report is presented in confusing fashion, butthe notion that ACE inhibitors may be beneficial in post-stroke dysphagia by raising substance P concentrationsand thereby enhancing the cough reflex is fascinatingand deserves further study.

Persistent Dysphagia after Laser UvulopalatoplastyIsberg A, Levring-Ja¨ghagen E, Dahlstro¨m M, Dahl-qvist ÅActa Otolaryngol 118:870–874, 1998

Uvulopalatopharyngoplasty is resection of the posteriorsoft palate, uvula, and tonsils for treatment of snoring orobstructive sleep apnea. Uvulopalatoplasty is a similarprocedure without tonsillar resection. It can be per-formed with laser or conventional steel scalpel (see be-low).

Seventy-nine patients underwent clinical and vid-eoradiographic evaluation a minimum of 2 yr after laseruvulopalatoplasty (LUPP). Twenty-one (27%) patientsreported persistent dysphagia postoperatively. The most

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

common complaints were choking at meals in 17 (81%),needing to concentrate during meals in six (29%), andnasal regurgitation and globus sensation each in four(19%). Three patients with unsatisfactory relief of snor-ing and daytime sleepiness regretted the operation be-cause of postoperative dysphagia.

The 21 patients with postoperative dysphagiawere studied videoradiographically, and 16 (76%) “dem-onstrated a deviant swallowing pattern.” There was pre-mature leakage into the pharynx without elicitation ofswallowing in 11 (52%) and bolus retention on the epi-glottis in eight (38%), in the valleculae in six (29%), andin both locations in five (29%). Two patients had sub-glottic aspiration. Five patients had no videoradiographicfinding.

Isberg et al. speculate that pharyngeal dysfunc-tion after LUPP could be due to altered oropharyngealsensation “as the postoperative sensory pharyngeal sig-nal differs from the code needed to evoke a swallowwhen the bolus enters the oropharynx.” They also pointout that snorers may be predisposed to pharyngeal dys-function, based on studies indicating progressive palato-pharyngeal nerve lesions in snorers. These lesions havebeen speculated to be due to mechanical trauma causedby low-frequency vibrations and stretching of tissue dur-ing snoring and apneas.

Persisting Dysphagia after Uvulopalatoplasty Per-formed with Steel ScalpelLevring-Jaghagen E, Nilsson ME, Isberg ALaryngoscopy 109:86–90, 1999

In their introduction the authors refer to the previouslysummarized article reporting dysphagia following LUPPand note that LUPP patients experienced markedly morepostoperative pain than patients following conventionalsteel scalpel uvulopalatoplasty (UPP). Levering-Jaghagen et al. suggest that post-LUPP dysphagia couldresult from either scarring or “a habitually deviant modeof swallowing developed to cope with severe postopera-tive pain.” They conducted a study of 68 patients fol-lowing UPP to test the hypothesis that post-UPP patientswould have a lower incidence of dysphagia comparedwith post-LUPP patients.

Patients were studied a minimum of 1 yr postop-eratively with a questionnaire and videoradiography.Twenty patients (29%) complained of post-UPP dyspha-gia. The most common complaints were coughing atmeals and nasal regurgitation in nine patients each(53%), needing to concentrate during meals in five(29%), and food sticking in the throat in four (24%).Three patients with postoperative dysphagia regretted

undergoing surgery, but most of the dysphagic patientsreported that the benefits of surgery exceeded their prob-lems with postoperative dysphagia.

Videoradiography showed “a deviant swallowingpattern” in 12 of the 17 patients with post-UPP dyspha-gia (71%). Ten of these 12 patients had premature leak-age without elicitation of swallowing. Seven had pha-ryngeal retention, and two had laryngeal vestibular pen-etration. Five patients with postoperative dysphagia hadno videoradiographic abnormality.

The hypothesis that post-UPP patients wouldhave lower incidence of dysphagia than post-LUPP pa-tients was rejected; the incidence of postoperative dys-phagia symptoms was virtually identical in the twogroups. As to specific symptoms, nasal regurgitation wasstatistically significantly more common after UPP thanafter LUPP. Levering-Ja¨ghagen et al. discuss possibleexplanations based on surgical techniques and healingprocesses. They conclude that with either surgical ap-proach, laser or conventional steel scalpel uvulopalato-plasty, patients should be forewarned about possible per-sistent postoperative dysphagia.

CommentsThese two companion studies are uncontrolled in severalrespects. Patients were not studied preoperatively, de-spite evidence that snorers may be vulnerable to pharyn-geal dysfunction as noted by the authors. Levring-Jaghagen et al. state that the patients with post-UPP dys-phagia had no dysphagic symptoms preoperatively, yetthe authors simultaneously admit that preoperative pha-ryngeal function in these patients was not known.

These studies also were uncontrolled in thatneither postoperative patients without dysphagia norhealthy subjects were evaluated videoradiographically.The prevalence of “deviant swallowing patterns” inpostoperative dysphagic patients may be falsely elevatedbecause of lack of controls and the inclusion of prema-ture leakage without elicitation of swallowing as an ab-normal finding. The purported abnormality of this find-ing, by far the most common videoradiographic findingin their patients with postoperative dysphagia, has beenquestioned [1–2]. In both articles, the authors fail to ad-dress the substantial numbers of patients with postopera-tive dysphagia complaints but without videoradiographicfindings, suggesting additional false positivity of theirdata.

References

1. Chi-Fishman G, Sonies BC: Normal, or abnormal—that is thequestion: pharyngeal delay for cookie swallow [abstract].Dys-phagia 14:120, 1999

2. Buchholz DW, Neumann S: Comments on selected recent dys-phagia literature.Dysphagia 14:113–115, 1999

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Aspiration: A Potential Complication to Vagus NerveStimulationLundgren J, Ekberg O, Olsson REpilepsia 39:998–1000, 1998

Vagus nerve stimulation (VNS) is a new treatment toreduce seizure frequency. Among the first seven con-secutive VNS-treated children (aged 4–18 yr) at one in-stitution, the parents of two observed increased coughingand swallowing difficulties during meals.

All seven children were studied by videoradiog-raphy. The five patients without VNS-associated dyspha-gia had little if any videoradiographic abnormality withVNS either off or on. The two symptomatic children hadsubstantially abnormal videoradiographic findings in-cluding aspiration scores that increased when VNS de-livered continuous trains of current (a mode that is notused clinically).

Lundgren et al. speculate that the mechanism ofVNS-associated dysphagia may relate to decreased re-laxation of the upper esophagus during swallowing orinterference with brainstem function including the soli-tary tracts and nuclei ambigui. Both children with VNS-associated dysphagia had previous histories of mild dys-phagia (evident by videoradiography performed withVNS off) and have severe mental and motor impairment,suggesting that these may be risk factors.

CommentsThe treatment of epilepsy with VNS is on the rise, andthis sentinel report should alert us to be vigilant for VNS-associated dysphagia. If further evidence substantiatesVNS as a cause of dysphagia, technical modifications ofVNS may be indicated.

Results of Reoperation on the Upper EsophagealSphincterRocco G, Deschamps C, Martel E, Duranceau A, TrastekVF, Allen MS, Miller DL, Pairolero PCJ Thorac Cardiovasc Surg 117:28–31, 1999

The authors retrospectively reviewed the results of reop-eration on the upper esophageal sphincter (UES) for re-current or persistent obstructive symptoms in 37 patientsat two institutions. The original indication for surgerywas a pharyngoesophageal (Zenker’s) diverticulum in 33(89.2%), oculopharyngeal dystrophy in three (8.1%), andmuscular dystrophy in one (2.7%). Twenty-six (70.3%)of the 37 patients undergoing reoperation had had oneprior UES operation, nine (24.3%) had had two opera-tions, and two (5.4%) had had three operations. Symp-toms leading to reoperation included “dysphagia” (unde-fined) in 35 (94.6%), “regurgitation” (undefined) in 23

(62.2%), and “episodes of aspiration” (undefined) in 12(32.4%).

All 37 patients underwent “barium roentgeno-graphic examination of the esophagus,” 13 (35.1%) hadesophageal manometry, eight (21.6%) had esophagos-copy, and five (13.5%) had radionuclide esophagogra-phy. Thirty of the patients (91.0%) with Zenker’s diver-ticulum were found to have a recurrent or persistent di-verticulum at reoperation. Of the 37 total patients, 23(62.2%) underwent diverticulectomy and cricopharyn-geal myotomy, seven (18.9%) underwent cricopharyn-geal myotomy alone, and the remainder had assortedprocedures.

There was no operative death, but complicationsdeveloped in 10 patients (27.0%). One patient hadaspiration pneumonia leading to respiratory arrest andrequiring emergency orotracheal intubation that re-sulted in impaction of a tooth in the floor of the mouthwith secondary cellulitis and sepsis. This patientsubsequently required laryngectomy for intractableaspiration.

Follow-up was complete in 34 patients (91.9%) ata median duration of 39 months (range4 2–149months). Thirty-two patients (94.1%) were improved, in-cluding excellent results in 26 (76.5%), good in two(5.9%), fair in four (11.7%), and poor in two (5.9%)patients. The authors conclude that reoperation forpatients with persistent or recurrent symptoms afterinitial UES surgery is associated with acceptable mor-bidity and mortality, and most patients achieve reso-lution of symptoms. According to Rocco et al., diver-ticulectomy and cricopharyngeal myotomy are the treat-ments of choice for symptomatic patients with recurrentZenker’s diverticulum, and patients with recurrent oro-pharyngeal dysphagia (presumably related to neurologi-cal disease) should be treated with a cricopharyngealmyotomy.

In the discussion following the article, Dr. Roccoclarified that in almost all reoperations on patients withZenker’s diverticula an incomplete myotomy, especiallydistally, had been performed in the first place.

CommentsWe are surprised that the preoperative evaluation ofthese complicated cases—patients being consideredfor reoperation on the UES—would be limited tobarium esophagography and only occasional manometryand esophagoscopy. There is no mention of video-fluorographic swallowing studies having been per-formed, which we would think necessary not onlyto evaluate fully the nature of structural problemsaround the UES but also to look for neurogenic oropha-ryngeal dysphagia, the presence of which might be a factorin deciding whether to perform reoperation and what type.

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Although the authors’ findings and conclusionsmay apply to patients with persistent or recurrent Zenk-er’s diverticula alone, this report is not generalizable topatients with neurogenic dysphagia (and without diver-ticula) for whom repeat cricopharyngeal myotomy mightbe considered. This report does not distinguish the out-comes of the small number of patients with neurologicaldisorders from the majority of the patients with Zenker’sdiverticula, and we wonder if the patients with neuro-logical disorders were among those with relatively pooroutcomes.

Gut Feelings About Recovery after Stroke: The Or-ganization and Reorganization of Human SwallowingMotor CortexHamdy S, Rothwell JCTrends Neurosci 21:278–282, 1998

Hamby and Rothwell review the state of knowledgeabout cortical control of swallowing in man based on

direct brain stimulation, lesional data, and transcranialmagnetic stimulation. Data indicate that there is asym-metric hemispheral representation for swallowing inmost individuals, independent of handedness.

Recovery from dysphagia following unilateralhemispheral stroke appears to arise from increasedactivity in projections from the undamaged hemis-phere to the brainstem over a period of weeks. Hamdyand Rothwell speculate that future therapies mightbe targeted at stimulating reorganization of cortical con-trol of swallowing in the intact hemisphere by eitherincreasing sensory input or applying repetitive stimulito it.

CommentsThis easy-to-read, brief, and comprehensive review of arapidly developing area of new knowledge is highly rec-ommended.

Final CommentLooking back at the range of subject matter and methods in the articles reviewed, from counting numbers of tooth pairsas described by Hildebrandt et al. to the sophisticated neurophysiological techniques discussed by Hamdy and Rothwell,we are again reminded and still impressed by the breadth of the uniquely multidisciplinary field of dysphagia: from theedentulous to the sublime.

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