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 which refers to the construction of a deep state of psychophysical relaxation. 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 1) the conscientiousness of the body part by part, deeply relaxing each one; 2) the conscientiousness of breathing that becomes free, smooth and harmonious until inhaling and exhaling seem to be a single continuous movement; 3) 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. When staying with an empty mind is not possible, staying with the mind conscious of the rhythm of the breath. All types of Yoga work with the practise of Yoga Nidra.
The importance of Yoga Nidra in dealing with stuttering can be understood if we think that the speaker who stutters, marked by a stigmatized image, has the desire to control the flow of his speech. But the flow of speech is not subject to control, it is automatic, [it stems from the meaning that is built up throughout the speech, in such a way that] one word "pulls" the other and they go, so to speak, slipping from the mouth. In order to achieve the desired control, the speaker starts to foresee the place where his stuttering will appear, that is, he feels or sees that he will stutter, knows that he will stutter, the sensation that he will stutter pursues him and this tenses the muscles involved in speaks actually producing stuttering.
From the practice of Yoga Nidra, I help the patient to become aware of the way his mind works in the production of speech and in the production of stuttering. He begins to perceive and recognize that it flows in the moments when he lets himself speak freely without controlling and stutters in the moments when he speaks anticipating the place of stuttering. This allows you to see / feel the strong relationship between anticipating stuttering and locking muscles.
The continuity of this practice allows him to understand that at the moment of the crash he can focus on what is happening in his body, in his muscles, instead of being in the "mental prison" formed by: fear of stuttering, anticipating stuttering and trying. The concrete perception of the body and muscles allows you to release the locks easily.
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.