title: The ubiquity of contraction enhanced H reflexes: normative data and use in the diagnosis of radiculopathies.
abstract: Surface recorded contraction enhanced H reflexes to single stimuli were obtained from muscles supplied by the C5, 6, 7, 8, L3, 4, 5, S1 and 2 nerve roots. For each of 12 such muscles, these reflexes were recorded from 25 control subjects as well as standard unenhanced H reflexes from the gastrocnemius muscles. Amplitude and latency criteria for normality were determined. Thirty-two patients with typical histories and physical findings of radiculopathy secondary to degenerative disease of the spine (C6 nerve root - 9 patients, C7 - 10, C8 - 4, L4 - 4, L5 - 4, S1 - 1) were studied with these H reflexes and the needle electrode. Thirty patients had H reflex abnormalities appropriate to the signs and symptoms. Eighteen had absent H reflexes and 16 had abnormalities to amplitude criteria. None were abnormal by latency criteria. Twelve patients had abnormal needle examinations and all also had abnormal H reflexes. These results indicate that contraction enhanced H reflexes are ubiquitous, readily obtainable and sensitive to the presence of clinically clear-cut radiculopathies.
authors.affiliation: Department of Neurology, Stanford University School of Medicine, CA.
authors.forename: J C
authors.initials: JC
authors.lastname: White
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D009132:Muscles / Q000502:physiology; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology; D011930:Reaction Time; D013126:Spinal Nerve Roots