4/19/2023 0 Comments Reactivity definition psychology![]() ![]() Somatosensory impairment could be explained by brain injuries (severe IVH ) and cystic PLV ( Wickremasinghe et al., 2013), particularly cerebral white matter disturbances. Somatosensory modulation could be impaired as children born prematurely have been described as being highly responsive and defensive to their external environmental stimuli ( Case-Smith et al., 1998 Walker et al., 2009 Eeles et al., 2013 Wickremasinghe et al., 2013). ![]() ![]() Children born preterm could exhibit hyposensitivity (threshold) in thermal ( Walker et al., 2009) and tactile perception, in kinesthesia, and graphesthesia ( DeMaio-Feldman, 1994 Wickremasinghe et al., 2013). The risk of somatosensory processing impairment decreases with GA ( Adams et al., 2015 ). Premature birth could compromise both somatosensory registration and sensory modulation. Emilie Bourel-Ponchel, in Handbook of Clinical Neurology, 2020 Impact of prematurity The following section illustrates how these tests have helped identify the underlying mechanisms of three painful syndromes.įabrice Wallois. This result is strong evidence of altered central pain modulation and CS.Ĭombining the above procedures into one methodological approach provides a clinical decision-making tool that facilitates diagnosis and choice of treatment. Mechanical stimulation cannot distinguish between these alternatives, but recent evidence shows that a ratio between the electrical pain and the detection threshold of <2.0 may indicate altered central nervous system processing of Aβ fiber input ( Sang, C. Theoretically, this can be mediated by either sensitized pain fibers or a functional change in large-diameter Aβ fibers that usually only mediate the sense of touch. One striking abnormality is dynamic mechanical allodynia, pain to light brushing of the skin. CS is characterized by spontaneous pain and evoked pain abnormalities that can cross dermatomes. et al., 1998 2001).īoth neuropathic and intense nociceptive pain can initiate and maintain a condition of spinal central sensitization (CS). et al., 1998), and lowered pain thresholds to this type of stimulation have been found in patients with orofacial myofascial pain ( Svensson, P. Following injection of hypertonic saline to the masseter muscle, mechanical stimuli applied into the overlying skin induced significant increases in the verbal rating score ( Svensson, P. In the orofacial region, there is both experimental and clinical evidence for this effect. ![]() et al., 2002).Īlthough the mechanisms are not clear, muscle-induced pain may result in the opposite effect, that is, reduced large nerve fiber sensitivity reflected by elevated electrical or mechanical detection thresholds ( Stohler, C. et al., 2001 2003) and reproduced in a model of inflammatory trigeminal nerve neuropathy ( Benoliel, R. This increased detection sensitivity has been demonstrated in clinical studies and in animal spinal nerve models ( Eliav, E. For example, early perineural inflammation produces short-lasting large myelinated nerve fiber hypersensitivity that results in reduced detection to electrical and mechanical stimuli. In contrast to the neuropathic process of mechanical nerve damage, specific nociceptive processes may provide a different, identifiable sensory signature. Partial damage may be followed by either hypo- or hypersensitivity accompanied by ongoing neuropathic pain ( Benoliel, R. Mechanical nerve damage or total nerve transection is characterized by myelinated and unmyelinated nerve fiber hyposensitivity reflected in elevated detection thresholds to heat, electrical, and mechanical stimulation ( Dao, T. Eliav, in The Senses: A Comprehensive Reference, 2008 5.61.1.2.2 Quantitative sensory testing signatures of pathological conditions ![]()
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