J Harlaar | PubMed Health

PubMed1992

Diagnostic blocks of the tibial nerve in spastic hemiparesis. Effects on clinical, electrophysiological and gait parameters.

The value of a diagnostic block (DB) of the tibial nerve in 17 hemiparetic patients with gait disturbances was investigated. The purpose of this study was to find instruments that help to select patients who will benefit from a long lasting peripheral nerve block. The manually elicited ankle clonus and its abolition after injection of a local anaesthetic appeared to be a useful clinical test for the efficacy of DB. Electrophysiological tests proved valuable when DB failed to produce clinical effects. With a substantial number of blocked nerve fibres walking velocity did not deteriorate. Transient disturbances in sensation can be regarded as unwanted side effects that might adversely affect the walking ability. From the different aspects of gait an improved heelcontact demonstrated the functional gain in patients with a dynamic equinus foot. To differentiate between a dynamic equinus foot and fixed contractures, we recommend the use of a fast acting local anaesthetic for diagnostic nerve blocks.

Adult↗

PubMed1991

Electromechanical delay during knee extensor contractions.

The purpose of this study was to investigate the magnitude of electromechanical delay (EMD) and its possible dependence on muscle type, type of contraction, fatigue, level of force, initial muscle length, and muscle contraction velocity. This was achieved using an experiment that measured voluntary knee extensor torques and surface EMG activity for a variety of different contractile conditions in seven male subjects. EMD values were obtained using a cross-correlation technique in three experimental KIN-COM dynamometer conditions of vastus medialis, rectus femoris, and vastus lateralis. In the first condition, a series of 10 repetitive submaximal (50% and 70% MVC) isometric knee extensor contractions were performed at knee angles of 90 degrees and 130 degrees extension. In the second condition, 10 maximal isokinetic knee extensor contractions were performed during passive shortening and lengthening. As such, the dynamometer was used to passively move the knee joint at 30 degrees.s-1 and 60 degrees.s-1. Both during lengthening and shortening, the contractions occurred at an angular position of 110 degrees. In the last condition, a repetitive submaximal isometric knee extensor fatigue test was performed for 100 s (150 contractions). At 10, 40, and 90 s during the time course of this fatigue test, a series of 10 contractions were recorded. To avoid a phase lag, which is introduced with one-way filtering, the EMG was processed with a bidirectional low-pass filter application. A significant main effect in EMD for the factor level of force was found. The EMD values obtained at a force level of 50% MVC were longer than at 70% MVC (107 vs 98 ms).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗