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Home | Self Image | Therapy | Speech | Psychotherapy | Research | Topics | Conclusion | Inhibition Hypothesis |
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![]() Marilyn Monroe seems
to have been taught by
a speech coach to use exaggerated mouth movements and a |
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This situation can be thought of as a "two hands clapping" problem -- as contrasted with the "one hand clapping" spontaneity of the Zen koan. To clap, the primary role of the conscious brain is to initiate the activity. After initiation, the actual movements are controlled by automatic subcortical brain activity, including refinement by motor and memory feedback circuits in the cerebellum. To successfully make a clapping sound, both hands must come together in just the right way, but this happens spontaneously, controlled by a high degree of cooperation among components of the brain which act totally automatically. (Watch an infant try to clap to see what happens without this precision.) One doesn't have to think about bringing both hands together because the mind doesn't perceive the hands as two objects separate from the body, which is really one continuous organism that exists in a unity of being. When the child becomes aware of his speech as a "problem," s/he subverts the mind's intuitive automatization of the speech articulators, voicing apparatus, and support systems (breathing, etc.) and attempts to initiate conscious control and correction of speech as it is occurring. Conscious control itself is not the problem, however. (And simply "letting go" is not the cure.)Children who are not predisposed to stuttering can exert conscious control over their speech, with the result that they talk more slowly and purposefully, but they do not experience an inhibition of speech. A disorder occurs when conscious control fails to produce the desired and expected outcome -- fluent speech. Stuttering behavior results from the automatization of maladaptive speech behaviors to which the child resorts because they are intermittently successful in helping him overcome an instinctual and involuntary inhibition of speech. This involuntary inhibition or "freeze" response -- a self-preservation reaction -- is the real core of stuttering. It is felt internally as a loss of control or as an inability to speak. And it is something with which every person who stutters is familiar. To speak in "the right way," or to push through or overcome the mysterious feeling of not being able to speak, the untutored child uses ad-libbed and maladaptive movements and contortions of the neck, larynx, mouth and face. This introduces increased tension into the muscles used to articulate speech, which has the effect of increasing their ballistic potential. As small dysfluencies such as bouncing repetitions, prolongations and small blocks begin to be amplified by the increased tension, the child perceives a greater need to control the speech articulators using extreme measures. There is a wonderfully sophisticated sensori-motor feedback system that works on the unconscious level to control these muscles. But the child's attempts to control this system subvert normal speech, which is a fluid activity that requires smooth transitions between articulatory positions that are continually changing to accommodate a corresponding flow of language, breath, and sound. Escalating dysfluencies -- which may become spasmodic repetitions, jaw tremors, head jerking and other noticeably different accessory behaviors, result in escalating worry, anxiety, and stress and even more muscular tension. Soon, the child is not just reacting to the original dysfluencies, but also to more extreme ballistic movements caused by the abnormal control and tension. Emotions involved in stuttering moments create a harmful distraction as the child is engulfed in feelings of inadequacy, frustration, fear, anger, being "out of control" -- the entire range of feelings to which psychologists may later attribute the onset of stuttering. The early childhood years are a time when competence and self-control are rewarded by parents, peers, and the child's super-ego. Children are also primed to notice and respond to discrepancies in their environment and their own behavior (Kagan 1996). The original dysfluencies -- caused in some by the use of language that is too complex for a developing speech-motor system and in others by other factors -- may offer a striking discrepancy from speech which was previously fluent. Children also obtain a significant amount of positive feedback from their early speech. If the smiles of adults turn to quizzical, bemused, or even angry expressions, this discrepancy will alert sensitive children that something is wrong and they may try to compensate. In some children, this compensation can rapidly result in "borderline" stuttering, an increased number of part-word repetitions and prolongations. When borderline stuttering starts to be perceived by the child's conscious and subconscious mind as a loss of control and competence, speech can become a survival issue, triggering survival responses, such as freezing, a reaction mediated by the amygdala, a small structure associated with the so-called "limbic system" at the base of the forebrain. Depending upon the child's environment, traumatic events may begin to happen, during which the child stutters, is ridiculed by listeners, and feels helpless to control his speech. Only one or two such events are needed for the child to begin to react with shame and fear to his loss of control and the increasing feeling of helplessness. At this point, the speech mechanism becomes subject to an instantaneous "freeze" survival response, a natural response to an undifferentiated threat. Even the most severe and unpleasant speech tensions and blocks are rewarded when they intermittently result in escaping the moment of stuttering. In the context of the survival situation the brain perceives, these maladaptive behaviors become deeply learned (conditioned) unconscious strategies to preserve the person from danger. A possible effect of the underlying inhibitive reactivity could be the apparent disabling of key left hemisphere activity recently seen in PET scans of people who stutter. This effect may result from inhibiting actions in other parts of the brain, such as the anterior cingulate cortex, or simply from the disruption of speech-language and speech-motor coordination and automatic motor programs involving circuits in the basal ganglia and brain stem. The attempt to inhibit speech may simply be the brain's corrective strategy to prevent the person from speaking in a disordered or unpredictable way -- or it may be a survival strategy, to protect the person from suffering humiliation or loss of status, which is a devastating consequence for any organism. There are a variety of neural circuits that may have weak points that are vulnerable to breakdown or inhibition, and this variation in individual stutterers may be one of the reasons for the many varieties of stuttering behavior. As indicated above, the amygdalae are involved in all human threat responses and survival reactions, including "freeze" and "fight or flight" responses. One of the aggravating factors that makes it difficult for the child to self-correct may be the recently discovered direct auditory pathway from the ears to the amygdalae, which by-passes the cerebral cortex, allowing circuits triggered by the amygdala to respond to a discrepant or conditioned auditory input that has been determined to be threatening before the cortical brain even hears it (LeDoux (1996) The Emotional Brain.) Perhaps even more than fluent speakers, PWS primarily monitor their speech with auditory feedback. Unfortunately, this is the same channel used by the brain as an early warning system for approaching danger. The amygdalae, working with the hippocampus, create a state of watchfulness when a situation associated with danger (or, in this case, dysfluency) exists. Once this specific speech situation or state is created and reinforced through the release of various hormones (including stress hormones) the possibility that stuttering may be triggered is increased. It must be remembered that this process is basically outside the stutterer's control. While in this excitatory state, when the stutterer initiates an "s" or an "f" with a tense articulatory posture that the unconscious feedback systems have learned to associate with dysfluent speech, the sensitive (and specialized) auditory neurons responsible for detecting specific threats may signal the amygdala or the associated areas it influences to trigger action potentials that inhibit, "freeze" or disable the speech-language mechanism. In conjunction with other cues, this may trigger the cascade of responses that set in motion the stuttering event. Given the extremely high background muscular tension and the apparent disabling of cortical speech areas, the stutterer's original conscious attempts to control or avoid speech or overcome the feeling of speech blockage often result in spasms, jaw and mouth tremors and movements designed to control the chaotic movements resulting from the original control attempts. One of the indications that the neo-cortical speech and language centers are essentially disabled during such events is the persistent use of the reduced and vegetative "schwa" vowel ("uh") which commonly occurs in part-word repetitions and is a well-recognized danger sign for chronic stuttering. Out-of-control part-word repetitions may look like the actions of a servo-motor that continues to be activated while being decoupled from its control system. These chaotic chugging or flapping movements are extremely disturbing to those who are experiencing them and can be horrifying to observers. It is no wonder that people who stutter often learn to speak with tightly clenched jaws. Yet another survival response may be the release of neurotransmitters that serve to anesthetize the stutterer to the emotional pain, embarrassment, and shame he/she is experiencing. During severe stuttering episodes the person will lose consciousness of what is happening (a condition named petit mort by Van Riper), compounding the difficulties of later corrective therapy. This "reacting to reactions," covered over with a loss of presence and awareness, may help create the illusion of impenetrability characteristic of severe secondary (i.e., reactive) stuttering. With this impenetrability comes the persistence of severe stuttering, which is not an illusion. This persistence often carries the person through high school as a stutterer if there is no (or inadequate) intervention. There are cases of spontaneous recovery during the teenage years, but the longer one continues in this mode without effective treatment, the longer the eventual recovery process may take. Additional background on the model of stuttering proposed here can be obtained by reading A Reactive Inhibition Model of Stuttering Behavior. |
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