title: Independence of soleus H-reflex tests in control and spastic subjects shown by principal components analysis.
abstract: Different soleus H-reflex tests are used in the study of neurophysiological mechanisms of motor control. We studied the interdependence pattern of a number of soleus H-reflex tests, i.e., vibratory inhibition, the ratio of the reflex response to direct muscle potential (H/M ratio) and the homonymous recovery curve with a principal components analysis in 48 healthy controls and 38 patients with signs of the upper motoneuron syndrome. In controls, the analysis showed 3 independent principal components (PCs). Vibratory inhibition and H/M ratio loaded on separate components. Late facilitation and late inhibition variables of the recovery curve loaded on the third component due to the positive correlation (P < 0.001) between these variables. In spastic patients the analysis identified 4 independent PCs corresponding with vibratory inhibition, H/M ratio, late facilitation and late inhibition variables, respectively. The findings suggest that the mutual independence of the different soleus H-reflex tests in patients with the upper motoneuron syndrome has retained the control situation to a large extent.
authors.affiliation: Graduate School Neurosciences Amsterdam, Department of Neurology, The Netherlands.
authors.forename: R B
authors.initials: RB
authors.lastname: Willemse
authors.forename: J H
authors.initials: JH
authors.lastname: Koelman
authors.forename: L J
authors.initials: LJ
authors.lastname: Bour
authors.forename: B W
authors.initials: BW
authors.lastname: Ongerboer de Visser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004576:Electromyography; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000503:physiopathology; D015999:Multivariate Analysis; D009128:Muscle Spasticity / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D011999:Recruitment, Neurophysiological / Q000502:physiology