Let me start with your last question – the matter is not about considering differences between Yoga Nidra and other Yoga, since Yoga Nidra is a part of Yoga in general that is related to the disengagement of the senses. To explain what this means let’s begin by considering that Yoga is union.
Different aspects can approach this concept of union. To the matter here required we are focusing the union between body and mind through conscience (considering mind as feelings and thoughts). To come into contact with this union, Yoga Nidra proposes the conscientiousness of the body to the practitioner, part by part, in a deep relaxation of each part; the conscientiousness of breathing that becomes free, smooth and harmonious until inhaling and exhaling seem to be a single continuous movement; the conscientiousness of what goes through the mind – feelings, thoughts and images – not allowing to be dragged by them but, instead, remaining empty, still minded (if remaining still minded is not possible, lead the mind in being aware of the breathing rhythm). All types of Yoga work with the practise of Yoga Nidra.
The importance of Yoga Nidra in treating stuttering can be understood if we consider that the speaker that stutters – marked by a stigmatized image of himself – has the discursive function stimulated by the desire of controlling the flow of the speech. But the speech flow, as a mater of fact, cannot be controlled. It is a consequence of the meaning that is being built during the discourse in such way that a word “draws” another and they slide from the mouth – so to speak. Producing words is automatic and spontaneous. In other words, we know how to speak, but do not know the way we do it. To fulfil the desired control, the speaker begins to predict where the stuttering will show up (appear / emerge). Usually the prediction of this placing is unconscious - the person just feels that stuttering will happen, knows that will stutter – and is chased by the firm sensation that will certainly stutter.
By conducting speaking experiences lived during a Yoga Nira practice I help patients in becoming conscious of the way their mind works when producing speech and stuttering. They begin to realize and recognize in themselves the moments in which their speech flows free of any control, and when they speak anticipating the place of stuttering. This (The Yoga Nidra practice) allows them to see / feel the intense articulation between foreseeing stuttering and stuck muscles (this articulation is very meaningful, since stuttering is stigmatized and its anticipation could only stuck the muscles in an attempt to restrain stuttering).
The continuity of this practice (experiencing speech by practicing Yoga Nidra) allows patients to slide away from their “mental prison” created by this ante vision of stuttering, engage in ways to “dribble” it, and connect with what is happening to their bodies. This is when they become conscious that their muscles are stuck and this perception allows loosing them.
That is why Yoga Nidra is a technique that allows working, in therapeutic interaction, with the conscientiousness of the relation body / mind either in the production of a stuttering speech, or of a fluent speech and, therefore, help patients to dislocate from the first to the latter.