Etiology

Although the etiology of stuttering is not fully understood, there is?ÿstrong evidence to suggest that it emerges from a combination of constitutional and?ÿenvironmental factors. Geneticists have found indications that a?ÿsusceptibility to stuttering may be inherited and that it is most?ÿlikely to occur in boys.1,2,3 Further support for inheritance comes from twin?ÿstudies that have demonstrated a higher concordance for stuttering?ÿamong both members of identical twin pairs than fraternal twin pairs.4,5?ÿCongenital brain damage is also suspected to be a predisposing factor?ÿin some cases.1 For a large number of children who stutter, however,?ÿthere is neither family history of the disorder nor clear evidence of brain?ÿdamage.

Brain imaging studies conducted in many laboratories throughout the?ÿworld indicate that adults who stutter show distinct anomalies in?ÿbrain function.6,7,8 In contrast with normal speakers, individuals?ÿwho stutter show deactivation of left-hemisphere sensorimotor centers?ÿand over-activation of homologous right-hemisphere structures during?ÿboth stuttered and nonstuttered speech. The essential defect is?ÿhypothesized to be a lack of sensorimotor integration necessary to?ÿregulate the rapid movements of fluent speech. Both temporary fluency (induced through singing or choral reading) and more permanent?ÿfluency (as a result of behavioral treatments) appear to normalize?ÿthe activation patterns.9 The onset of stuttering is
typically during the period of intense speech and language?ÿdevelopment as the child is progressing from 2-word utterances to the use of complex sentences, generally between the ages of 2 to 5 but sometimes as?ÿearly as 18 months. The childƒ??s efforts at learning to talk and the?ÿnormal stresses of growing up may be the immediate precipitants of?ÿthe brief repetitions, hesitations, and sound prolongations that?ÿcharacterize early stuttering as well as normal disfluency*. These?ÿfirst signs of stuttering gradually diminish and then disappear in?ÿmost children, but some children continue to stutter. In fact, they?ÿmay begin to exhibit longer and more physically tense speech behaviors as they respond to their speaking difficulties with?ÿembarrassment, fear, or frustration. If referral to a speech-language?ÿpathologist for parent counseling and treatment is made before the?ÿchild has developed a serious social and emotional response to stuttering, prognosis for recovery is good.10,11,12

?ÿ*The term ƒ??disfluencyƒ? means a hesitation, interruption, or disruption in speech. It may be normal or, as in the case of stuttering, it may be abnormal.

  1. 1. Andrews, G., Craig, A., Feyer, A. M., Hoddinot, S., Howie, P., and?ÿNeilson, M. (1983). Stuttering: A review of research findings and?ÿtheories circa 1982. Journal of Speech and Hearing Disorders, 48, 226-246.?ÿ
  2. Bloodstein, O. (1995). A Handbook On Stuttering (5th ed.). San?ÿDiego, CA: Singular Publishing Group, Inc.
  3. Drayna, D. (2004) Results of a Genome-Wide Linkage Scan for?ÿStuttering. In American Journal of Medical Genetics 124A:133-135.
  4. Felsenfeld, S. (1996). Epidemiology and genetics of stuttering. Chapter in R. Curlee and G. Siegel (Eds.), Nature and Treatment of Stuttering: New Directions. Boston: Allyn &?ÿBacon.
  5. Howie, P. M. (1981). Concordance for stuttering in monozygotic and?ÿdizygotic twin pairs. Journal of Speech and Hearing Research, 24, 317-321.
  6. Fox, P.T., Ingham, R., Ingham, J.C., Hirsch, T.B., Downs, J.H.,?ÿMartin, C. et al. (1996). A PET study of the neural systems of stuttering.Nature, 382:158-162.
  7. Fox, P.T., Ingham, R.J., Ingham, J.C., Zamarripa, F., Xiong, J.-H., and Lancaster, J.L. (2000).?ÿ Brain correlates of stuttering and syllable production: A PET performance-correlation analysis. Brain, 123:1985-2004.
  8. Sommer, M., Koch, M.A., Paulus, W., Weiller, C. and Buchel, C.?ÿ(2002). Disconnection of speech-relevant brain areas in persistent?ÿdevelopmental stuttering.?ÿ Lancet, 360: 380-383.
  9. Ingham, R.J. (2003). Brain Imaging & Stuttering [Special Issue].?ÿJournal of Fluency Disorders, 28 (4).
  10. Harrison, E. and Onslow, M. (1998), Early Intervention for?ÿStuttering: The Lidcombe Program. In R. F. Curlee (Ed.), Stuttering?ÿand Related Disorders of Fluency, (2nd ed.). NY, NY.: Thieme.
  11. Pellowski, M., Conture, E., Roos, J., Adkins, C. & Ask, J. (2000,?ÿ
    November). A parent-child group approach to treating stuttering in young?ÿchildren: treatment outcome data. Paper presented to Annual?ÿConference of American Speech-Language-Hearing Association,?ÿWashington, DC.
  12. Starkweather, W., Gottwald, S., and Halfond, M. (1990). Stuttering Prevention A Clinical Method. Englewood Cliffs, N.J.: Prentice-Hall.
  13. Yairi, E. (1997). Home environment and parent-child interaction?ÿin childhood stuttering. In R. Curlee and G. Siegel, Nature and?ÿTreatment of Stuttering: New Directions. Boston: Allyn & Bacon.
  14. Yairi, E. & Ambrose, N. (2005). Early Childhood Stuttering: For Clinicians By Clinicians, ProEd, Austin, TX.

Guitar, B., & Conture, E. G. (Eds.) (2006). The child who stutters: To the pediatrician.?ÿFourth edition, publication 0023. Memphis, TN: Stuttering Foundation of America.