Sensorimotor control in the congenital absence of functional muscle spindles.

Autor: Macefield VG; Department of Neuroscience, Monash University, Melbourne, Victoria, Australia., Smith LJ; School of Medicine, Western Sydney University, Sydney, New South Wales, Australia., Norcliffe-Kaufmann L; Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA., Palma JA; Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA., Kaufmann H; Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA.
Jazyk: angličtina
Zdroj: Experimental physiology [Exp Physiol] 2024 Jan; Vol. 109 (1), pp. 27-34. Date of Electronic Publication: 2023 Apr 08.
DOI: 10.1113/EP090768
Abstrakt: Hereditary sensory and autonomic neuropathy type III (HSAN III), also known as familial dysautonomia or Riley-Day syndrome, results from an autosomal recessive genetic mutation that causes a selective loss of specific sensory neurones, leading to greatly elevated pain and temperature thresholds, poor proprioception, marked ataxia and disturbances in blood pressure control. Stretch reflexes are absent throughout the body, which can be explained by the absence of functional muscle spindle afferents - assessed by intraneural microelectrodes inserted into peripheral nerves in the upper and lower limbs. This also explains the greatly compromised proprioception at the knee joint, as assessed by passive joint-angle matching. Moreover, there is a tight correlation between loss of proprioceptive acuity at the knee and the severity of gait impairment. Surprisingly, proprioception is normal at the elbow, suggesting that participants are relying more on sensory cues from the overlying skin; microelectrode recordings have shown that myelinated tactile afferents in the upper and lower limbs appear to be normal. Nevertheless, the lack of muscle spindles does affect sensorimotor control in the upper limb: in addition to poor performance in the finger-to-nose test, manual performance in the Purdue pegboard task is much worse than in age-matched healthy controls. Unlike those rare individuals with large-fibre sensory neuropathy, in which both muscle spindle and cutaneous afferents are absent, those with HSAN III present as a means of assessing sensorimotor control following the selective loss of muscle spindle afferents.
(© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)
Databáze: MEDLINE
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