title: Ankle clonus and its relationship with the medium-latency reflex response of the soleus by peroneal nerve stimulation.
abstract: Ankle clonus and soleus medium-latency reflex are stretch-induced responses. Clonus is traditionally considered to be the result of oscillation in the group Ia mediated spinal stretch reflex but the soleus medium-latency reflex response originates mainly from the activation of group II afferents. The medium latency reflex response (MLR) was recorded in soleus muscle by peroneal nerve stimulation and clonus beats were recorded in soleus muscle using EMG in 19 spastic patients. The dorsiflexion (DF) and plantarflexion (PF) times of clonus and the half-period were calculated based on accelerometric measurements in 11 patients. The MLR of the soleus was 73.63 ± 8.9 ms. The half-period of the clonus was 79.34 ± 12.31 ms. The difference between the MLR and half-period was significant. The PF was 71.75 ± 6.73 ms, and the DF was 88.63 ± 10.83 ms. The difference between the soleus MLR and PF part of the clonus beat was not significant. The PF part of the clonus beat is due to soleus muscle contraction and controlled by the neural part of the oscillation. There may be relationship between the soleus MLR and the PF part of the clonus. Clonus is considered to be the result of oscillations in the group Ia spinal stretch reflex, but there is sufficient time for group II afferents to be involved.
authors.affiliation: Akdeniz University Hospital, Neurology Department, Antalya, Turkey. uysalh@akdeniz.edu.tr
authors.forename: Hilmi
authors.initials: H
authors.lastname: Uysal
authors.forename: Ismail
authors.initials: I
authors.lastname: Boyraz
authors.forename: Süha
authors.initials: S
authors.lastname: Yağcıoğlu
authors.forename: Fügen
authors.initials: F
authors.lastname: Oktay
authors.forename: Pınar
authors.initials: P
authors.lastname: Kafalı
authors.forename: Ergin
authors.initials: E
authors.lastname: Tönük
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology*; D009207:Myoclonus / Q000503:physiopathology*; D010543:Peroneal Nerve / Q000503:physiopathology*; D011930:Reaction Time; D012026:Reflex, Stretch