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From: Tom Weidig (thestutteringbrain.blogspot.com)
Date: 16 Oct 2005
Time: 14:47:43 -0500
Remote Name: 84.138.147.134
This is one of the most intruiging aspects of persistent developmental stuttering. It is the main challenge for people who believe that psychological issues are only consequences or re-enforcers of symptons. Many things about PDS are still uncertain, but I think there is/are explanations. 1) We need to realise that such effects not only happen in PDS. For example, a friend of mine is a doctor, and he told me that many Parkinson patients have very little shaking before the doctors enter the room, and heavily start shaking during the visit! Or nearly deaf people also have good and bad days and good and bad situations where their hearing deteriorates or becomes better. But no-one would suggest that the variability of their condition is proof of a psychological origin of their condition. 2) Situations with increased stuttering are typically situations where the brain has more work to do. When you are alone, your brain has far less work. But when you are around people (or think that you are around people), your brain has so much more workload: applying a social filter, coordinating the appropriate body language, increased stress, increased tension, responding to other people's ideas, future scenario analysis of your planned message and so on. If you think of stuttering as an unstable speech system, it is clear that more work means less stability. Like a road with road repairs is free of traffic jam on a Sunday, but not a Monday morning at 8. 3) Point two only explains why in some situations we should stutter more ON AVERAGE. But it does not say why sometimes we can be very fluent, even in situations of more workload. So I now distinguish between variability of stuttering, and fluency-enducing effect. Often, we mix the two: we put "less stuttering" equal to "more fluency". The two might well not be the same!! 4) According to a theory developed by Per Alm, Uni Lund, broadly speaking, there might be TWO pathways in the brain that regulate speech: an automatic one, and an active-control one. When you focus on your message, your brain runs the speaking for you (you speak without thinking about how to speak), and when you are focused on how you want to speak, you take control of your speech system. Once you have accepted this theory and you assume that PDS is instability of the automatic mode, everything makes more sense. If a person with PDS uses his active-control mode (like speaking with a foreign accent, imitating someone, speaking loudly, speaking in chorus, speaking in rhythm and so on), s/he becomes more fluent, because the unstable automatic mode is not used or only partially used. This would in my view explain the phenomena. OK, the details might turn out to be different, but at the very least I (or rather Per Alm) have shown that it is POSSIBLE to explain the effect WITHOUR mysterious and vague reference to psychological factors. Here is a citation from Per: "The theoretical work focused [on] the basal ganglia, leading to a model based on the dual premotor systems hypothesis (G. Goldberg, 1985, 1991), which defines two parallel premotor systems: the medial (basal ganglia + SMA), and the lateral (lateral premotor cortex + cerebellum). Stuttering is suggested to be caused by a disturbance of the medial system, in most cases in the basal ganglia. The core dysfunction is proposed to be impaired "go-signals" from the medial system, supposed to trigger the next motor segment in speech. Under some conditions speech control is shifted from the medial to the lateral system, thereby bypassing the dysfunction and resulting in fluent speech. The lateral system is suggested to be active when speech is combined with sensory input, like chorus speech or metronome. Also the effect of altered auditory feedback in reducing stuttering is proposed to be based on this mechanism. The lateral system is able control speech timing without sensory input, but this demands increased attention to some particular aspect of speech, as occurs in imitation of dialects, exaggerated rhythm, reduced speech rate, or role play. Also singing is suggested to be based on the lateral system." (Source: Per Alm, PhD thesis 2005, Lund University in Sweden)