Clinically silent dysfunction of dorsal columns and dorsal spinocerebellar tracts in hereditary spastic paraparesis

• Published in: Journal of the neurological sciences Vol. 125; no. 2; pp. 206 - 211
• Main Authors: Bruyn, R.P.M., van Dijk, J.G., Scheltens, P., Boezeman, E.H.J.F., de Visser, B.W.Ongerboer
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01.09.1994; Elsevier Science
• Subjects: Action Potentials; Adolescent; Adult; Aged; Biological and medical sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Evoked Potentials, Somatosensory; Female; H-Reflex; Hereditary spastic paraparesis; Humans; Male; Median Nerve - physiopathology; Medical sciences; Middle Aged; Nerve conduction; Nerve Degeneration; Neural Conduction; Neurology; Reaction Time; Sensory Thresholds; Severity of Illness Index; Somatosensory evoked potentials; Spastic Paraplegia, Hereditary - physiopathology; Spinal Cord - physiopathology; Tibial Nerve - physiopathology; Time Factors; Vibration; Vibration threshold; Nerve conduction; Somatosensory evoked potentials; Hereditary spastic paraparesis; Vibration threshold; Human; Hereditary spastic paraplegia; Electrodiagnosis; Nervous system diseases; Vibration; Pathophysiology; Central nervous system disease; Exploration; Degenerative disease; Somatosensory evoked potential; Cerebral disorder
• ISSN: 0022-510X; 1878-5883
• DOI: 10.1016/0022-510X(94)90037-X

Hereditary spastic paraparesis (HSP) is a neurodegenerative disorder, of which progressive spastic paraparesis is the clinical hallmark. Given the neuropathological evidence of degeneration of pyramidal tracts, dorsal columns, and dorsal spinocerebellar tracts, it is surprising that sensory symptoms are so indistinct compared to motor symptoms. We investigated the involvement of peripheral conduction and spinal proprioceptive pathways by nerve conduction studies, somatosensory evoked potentials of the median and tibial nerves, and quantitative assessment of the vibration perception thresholds of the hands and feet respectively in 32 patients suffering from HSP and healthy control groups. We did not find peripheral conduction abnormalities in HSP patients. Log-transformed vibration perception thresholds of the feet were abnormal in 13 32 HSP patients and in 0 64 controls ( p < 0.00001), while tibial nerve somatosensory evoked potentials were abnormal in 20 32 patients and in 1 17 controls ( p = 0.00001). The values for the upper extremities were within normal limits for nearly all subjects. In the HSP group, the neurophysiological disturbances did not correlate significantly with duration or severity of the disease, when age was controlled for, except for median nerve SSEP latency, which was affected by severity ( p = 0.0072). We conclude that neurophysiological methods detected proprioceptive, subclinical abnormalities in several HSP patients, which may reflect degeneration of the dorsal columns, and/or dorsal spinocerebellar tracts. Since we found no correlation with several disease variables, the fact that not all HSP patients displayed these abnormalities may be caused by anatomical variations in proprioceptive pathways, rather than by phenotypical heterogeneity.