stuttering Stuttering (or
stammering, as it is often called in Britain) is probably the best known and most researched
speech disorder, but perhaps the most difficult to define, to explain, and to treat, especially in adults. Both names are onomatopoeic: the essential features of stuttering are frequent repetitions and prolongations of sound or syllables. Other problems of fluency may also characterize stuttering, including blocking of sounds or interjection of words or sounds. However, the sudden sensation of a loss of control over the ability to produce an utterance distinguishes stuttering from other forms of unfluent speech. Another characteristic of stutterers, especially adults, is their avoidance of anticipated problem words and situations, in order to cope with the problem.
Chronic stuttering usually begins in early childhood (
development stuttering), although occasionally the disorder starts in adulthood (
acquired stuttering), usually as a result of brain damage. Stuttering seems to occur in all nationalities with a prevalence of approximately 1% and an incidence of 4% to 5%. Approximately 40% to 80% of children with the disorder recover, for various reasons, by the time they reach adolescence or adulthood. More males than females stutter: the ratio of males to female stutterers ranges from 2–3:1 in childhood, up to 4–5:1 by adulthood. The incidence of the disorder is much higher among other members of the family of a stutterer than in the general population: in other words, there is probably a genetic factor in this condition.
Stuttering may vary greatly in its frequency and severity in different situations. It is, for instance, dramatically reduced when speaking alone or reading aloud in chorus with an accompanist. Wearing headphones that alter the feedback of one's own voice can also reduce stuttering, and so too can the use of certain regular speech patterns (e.g. singing, unusual accents, speaking in rhythm). The reliability with which such techniques for inducing fluency can reduce or even abolish stuttering is considered a key to understanding the disorder — they also form the basis of some treatments.
The social and vocational effects of chronic stuttering may be quite devastating, perhaps because of the suspicion that it is the outward sign of a
personality disorder. However, there is remarkably little evidence that stuttering is related to any unusual personality characteristics or neuroses; and there is little support for the claim that stuttering is associated with anxiety. Many prominent individuals, including well-known actors and politicians, have managed to control their stuttering and achieve successful careers. Nevertheless, the handicapping effects of the disorder in children and adults are undeniable.
There is currently no accepted theory that offers a satisfactory explanation for all the features of stuttering. At different times, psychoanalytic or organic theories have held sway over research and/or therapy. Traditional, formal learning has been blamed; so too have errors in control systems in the brain. Most current researchers consider developmental stuttering to be a disorder of motor control, with strong genetic underpinnings, influenced by environmental factors. This position has gained support with evidence that signs of severe stuttering may appear almost as soon as a child starts to produce connected speech.
Recent studies of right-handed adult stutterers, using techniques for imaging activity in the brain, have revealed unusual patterns of activation and inhibition during stuttered speech, particularly in parts of the right hemisphere involved in hearing and the control of movement, and especially exaggerated in the
cerebellum. The unusual activity in these regions, which appears to occur only during speech, is very different when stuttering is reduced or absent as a result of strategies for improving fluency. These findings have intensified the search for a neurological system or systems that might be specifically related to stuttering.
The treatment of stuttering is an area of controversy. There is no evidence that any drug treatment is effective in removing stuttering in children or adults. The most convincing effects have been reported for behavioural treatments, although there is much debate about the evaluation of such therapy. Other forms of treatment emphasize learning to adjust to the disorder rather than removing the problematic behaviour.
Probably the most dramatic change to therapy for stuttering in the last decade is the use of mild verbal corrections for each occasion of stuttering, and verbal praise for periods of fluency, which has beneficial effects in treating young children. Recovery commonly occurs without treatment in the first year after onset, but this becomes less likely without intervention if the disorder persists. Indeed, there is an urgent need to correct the widely-held belief that children will recover from stuttering if their problem is merely ignored. Currently, the preferred therapies for older stutterers involve a combination of behavioural techniques and methods for training speech–motor strategies. However, there is no convincing evidence that these therapies result in complete recovery.
The most successful therapeutic approaches for adults and children involve three general features: first, a method that
establishes reduced stuttering or stutter-free speech under relatively controlled conditions; then a procedure for
transferring that improvement beyond the treatment setting; and finally, strategies for
maintaining that improvement. The most favoured techniques for establishing control over stuttering fall into three categories: behavioural methods based on rewarding performance; teaching stutterers to prolong their speech; and mechanical aids. These techniques are also often used in conjunction with control of the rate of speaking. Once improvement has been produced in the controlled conditions, ‘transfer’ procedures are used, which systematically introduce increasingly demanding speaking situations. The most successful maintenance procedures require intermittent management over periods lasting up to two or three years. Given the variability of stuttering across situations, over time, and with relatively slight alterations to the manner of speech production, stuttering therapy evaluation presents considerable challenges, which are now occupying the attention of clinical researchers.
Roger J. Ingham
Bibliography
Bloodstein, O. (1995). A handbook on stuttering. Singular, San Diego, CA.
Fox, P. T.,, Ingham, R. J.,, and Ingham, J. C., et al. (1996). A PET study of the neural systems of stuttering. Nature, 382, 158–62.
