Characteristics of the electromyographic patterns of lower limb muscles during gait in patients with Parkinson's disease when OFF and ON L-Dopa treatment

Abstract

The purpose of this study was to compare the electromyographic (EMG) behavior of the triceps surae (TS), tibialis anterior (TA), quadriceps and hamstring muscles of the lower limbs during self-initiated free gait in a group of patients (n = 15) with Parkinson's disease (PD), when OFF and ON L-Dopa, with that of normal controls. When OFF L-Dopa, we observed qualitative disturbances in muscle activation patterns, such as an absence or extreme reduction in TA activations in early stance or during the early and late swing phases. Other disturbances included flatter profiles of the TS activation burst at push off, and temporal alterations that included prolonged activation of the proximal muscles during the stance phase. Statistical analysis showed that the TA was the most affected muscle in most of the patients particularly during the activation burst in late swing (p < .0004). After medication (ON L-Dopa), the amplitude and timing of distal muscle activations became more similar to normal values, with the increase in EMG amplitude being dramatic in some patients. In the proximal muscles, the effects on EMG amplitude were less marked and prolonged activation often persisted even after the administration of L-Dopa.

Modulation of Cutaneous Reflexes From the Foot During Gait in Parkinson's Disease

“…Indeed, for particular muscles such as cBF an increase in response amplitude in some phases of the step cycle (second half of the contralateral step cycle) could be partly related to increased background EMG activity in PD subjects. This additional background activity is consistent with earlier findings since increased EMG activity patterns during parkinsonian gait have been reported for BF by several authors (Cioni et al 1997;Dietz et al 1997;Mitoma et al 2000). However, the changes in reflex amplitudes in cBF were not limited to the phases with increased background.…”

Speed related changes in muscle activity from normal to very slow walking speeds

“…In contrast, foot clearance must be achieved regardless of walking speed, which explains why TA activity during early swing appears to be relatively insensitive to speed changes. The strong speed sensitivity of the second TA burst (end swing-early stance) may be of clinical interest since the absence or reduced amplitude of this burst has been reported in Parkinsonian and hemiparetic persons [25,26]. Because these pathologies are usually associated with strongly reduced gait speeds, the results from the present study suggest that such phenomena could at least partly be explained by a speed effect.…”

Gait bradykinesia in Parkinson’s disease: a change in the motor program which controls the synergy of gait

“…Most studies focused their analyses on steady-state walking, reporting that leg EMG activity is reduced, and that the results are basically consistent with those observed in arm and finger movements (Evarts et al 1981;Wing 1988;Cioni et al 1997;Chee et al 2009). In addition, it has been reported that the impairment of gait initiation is associated with the visuospatial cognitive environment (Azulay et al 1999;Cummings and Steven 1992;Naismith et al 2010).…”

“…Bawa et al (2002) revaluated the nature of coritico-moto-neuronal connections onto tibialis anterior and soleus moto-neurons in human subjects, and found that all ankle flexor moto-neurons receive strong cortico-moto-neuronal connections, but the soleus receive very few. Cioni et al (1997) indicated that the EMG activity of the tibialis anterior muscles was reduced during steadystate walking in Parkinson's disease. In the present study of advanced cases of Parkinson's disease, the tibialis anterior EMG activity reduced the amplitude, and soleus EMG activity reduced the amplitude and approximated to the longlasting EMG activity.…”