Clonus is defined as an involuntary rhythmic muscle contraction that generally occurs in people who have sustained lesions involving descending motor pathways in the neuraxis, and is usually accompanied by other signs of reflex hyperexcitability such as spasticity. This paper hypothesizes that clonus arises when two conditions occur simultaneously: 1) the reflex pathway contains long delay time...

We assessed the prevalence of abnormal ankle reflexes in 1074 adult patients attending orthopaedic clinics and related it to age. Those with possible pathological causes of reflex loss were excluded. The absence of one or both reflexes was significantly related to increasing age; all patients under 30 years had both reflexes. Few had absent reflexes between 30 and 40 years, but over 40 years, t...

Although sensory feedback is important in regulating the timing and magnitude of muscle activity during locomotion few studies have evaluated how it changes after peripheral nerve lesions. To assess this, reflexes evoked by stimulating a nerve before and after denervating other nerves can be quantified to determine changes. The aim of this study was to investigate consequences of denervating an...

Involuntary responses to muscle stretch are often composed of a short-latency reflex (SLR) and more variable responses at longer latencies such as the medium-latency (MLR) and long-latency stretch reflex (LLR). Although longer latency reflexes are enhanced in the upper limb during stabilization of external loads, it remains unknown if they have a similar role in the lower limb. This uncertainty...

The current study compared the vibratory sensations at different sites, using a retrospective database of 547 Japanese diabetic patients. The vibratory sensation was assessed with a 128-Hz tuning fork at the medial malleolus, the great toe and the fifth toe. The vibratory sensations at different sites were significantly associated with one another (all P < 0.01). The vibratory sensation at one ...

During locomotion, contacting an obstacle generates a coordinated response involving flexion of the stimulated leg and activation of extensors contralaterally to ensure adequate support and forward progression. Activation of motoneurons innervating contralateral muscles (i.e., crossed extensor reflex) has always been described as an excitation, but the present paper shows that excitatory respon...

Control schemes for powered ankle-foot prostheses rely upon fixed torque-ankle state relationships obtained from measurements of intact humans walking at target speeds and across known terrains. Although effective at their intended gait speed and terrain, these controllers do not allow for adaptation to environmental disturbances such as speed transients and terrain variation. Here we present a...

A rapid plantar flexion perturbation applied to the ankle during the stance phase of the step cycle during human walking unloads the ankle extensors and produces a marked decline in the soleus EMG. This demonstrates that sensory activity contributes importantly to the enhancement of the ankle extensor muscle activation during human walking. On average, the EMG begins to decline approximately 52...

OBJECTIVE To evaluate the spasticity and electrophysiologic effects of applying extracorporeal shock wave therapy (ESWT) to the gastrocnemius by studying F wave and H-reflex. METHOD Ten healthy adults and 10 hemiplegic stroke patients with ankle plantarflexor spasticity received one session of ESWT on the medial head of the gastrocnemius. The modified Ashworth scale (MAS), tibial nerve conduc...

OBJECTIVE To evaluate the effectiveness of the Semmes-Weinstein monofilament examination (SWME) for diabetic peripheral neuropathy (DPN) screening at an outpatient clinic. METHODS Eighty-two type 2 diabetic outpatients were questioned about 13 subjective symptoms and tested for deep reflexes. They were examined using two types of quantitative sensory testing: SWME (using 4.31/2 g and 5.07/10 ...