Nondermatomal Somatosensory Deficits (NDSDs) and Pain: State-of-the-Art Review

Nondermatomal somatosensory deficits (NDSDs) are large sensory deficits not conforming to dermatomal/root territories, and no structural pathology accounts for them. They can be very mild or very dense, highly variable, or extremely fixed over time and may be very disabling. It is now accepted by mainstream pain science that they are the product of a central neurophysiological phenomenon. We demonstrated in this paper through literature review and through multiple clinical cases that NDSDs (a) have a psychobiological substrate at the level of the central nervous system, (b) are very frequently associated with chronic pain and/or psychotraumatic experiences, (c) occur very frequently in the context of conversion disorder, but (d) can also occur in the absence of conversion disorders, (e) can be superimposed on structural neurological deficits, and (f) respond positively, or at least in part, to sodium amobarbital (commonly referred to as the “truth serum”).