P30 Disturbed proprioception at the knee but not the elbow in hereditary sensory & autonomic neuropathy type III
Macefield VG[1,2,3], Smith LJ[1], Palma JA[4], Norcliffe-Kaufmann L[4] and Kaufmann H[4]
- School of Medicine, Western Sydney University, Sydney, Australia
- Baker Heart & Diabetes Institute, Melbourne, Australia
- NeuRA (Neuroscience Research Australia), Sydney, Australia
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, USA
Hereditary sensory and autonomic neuropathy type III features a marked ataxic gait that progressively worsens over time. We recently assessed whether proprioceptive disturbances can explain the ataxia. Proprioception at the knee joint was assessed using passive joint angle matching in 18 patients and 14 age-matched controls; 5 patients with cerebellar ataxia were also studied. Ataxia was quantified using the Brief Ataxia Rating Score, which ranged from 7 to 26/30. HSAN III patients performed poorly in judging joint position at the knee: mean (+/-SE) absolute error was 8.7+/-1.0deg and the range was very wide (2.8-18.1); conversely, absolute error was only 2.7+/-0.3deg (1.6-5.5) in the controls and 3.0+/-0.2deg (2.1-3.4) in the cerebellar patients. This error was positively correlated to the degree of ataxia in the HSAN III patients but not the cerebellar patients (1). However, using the same approach at the elbow revealed no significant differences in mean error in 12 HSAN III patients (4.8+/-1.2deg; 3.0-7.2) and 12 age-matched control (4.1+/-1.1deg; 2.1-5.5). Interestingly, microelectrode recordings from the peroneal nerve showed a complete absence of spontaneous or stretch-evoked muscle afferent activity (2), confirmed in the ulnar nerve. Clearly, the lack of muscle spindles compromised proprioception at the knee but not at the elbow, and we suggest that the HSAN III patients have learned to rely more on proprioceptive signals from the skin around the elbow. Indeed, applying longitudinal strips of elastic tape around the joint to increase tensile strain in the skin improved proprioception at the knee (3) but not the elbow.
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- Macefield VG, Norcliffe-Kaufmann LJ, Golding N, Palma JA, Fuente Mora C & Kaufmann H (2015) J Neurophysiol 115: 711-716