Cerebellar dysmetria at the elbow, wrist, and fingers

Abstract

1. The objective was to investigate in cerebellar patients with dysmetria the kinematic and electromyographic (EMG) characteristics of large and small movements at the elbow, wrist, and finger and thereby to determine the nature of cerebellar dysmetria at distal as well as proximal joints. Flexions were made as fast as possible by moving relatively heavy manipulanda for each joint to the same end position through 5, 30, and 60 degrees. 2. In normal subjects flexions at all joints were accompanied by similar triphasic EMG activity. Movements of increasing amplitude were made with increasing movement durations and increasing durations and magnitudes of initial agonist EMG activity. Antagonist activity often appeared to have two components: one coactive with the initial agonist burst but starting later, the other reaching its peak at about peak velocity. 3. Cerebellar patients with dysmetria showed hypermetria followed by tremor at all three joints when movements were made with the manipulanda. Hypermetria was most marked for aimed movements of small amplitude (5 degrees) at all joints. 4. A characteristic of cerebellar disordered movements, which could be present at all amplitudes and all joints, was an asymmetry with decreased peak accelerations and increased peak decelerations compared to normal movements. Both the asymmetry and the hypermetria for small amplitude movements could be used clinically as sensitive indicators of cerebellar dysfunction. 5. The EMG abnormalities accompanying hypermetria and asymmetry were a more gradual buildup and a prolongation of agonist activity and delayed onset of antagonist activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of multiple functionally distinct cerebellar regions in visual discrimination: a human functional imaging study

“…This fits the clinical finding that mainly rapid movements are impaired in patients with cerebellar lesions (Hore et al, 1991;Berardelli et al, 1996). Several authors (Ivry and Keele, 1989;Jueptner et al, 1995;Tesche and Karhu, 2000;Dreher and Grafman, 2002;Ivry et al, 2002) have suggested a timing function for the cerebellum.…”

Brain activation patterns during measurement of sub- and supra-second intervals

“…Because the durations relevant for movement (for instance in muscle phasing and coordination) fall within the sub-second range (Hore et al, 1991), it has been suggested these short intervals may be measured within the motor system. Observation that cerebellar lesions can lead to deficits in movement-related timing (Ivry & Keele, 1989;Ivry, Keele, & Diener, 1988) and in non-motor timing at the milliseconds range (Casini & Ivry, 1999) have combined to implicate this structure as a candidate locus for such processes (Ivry, 1996(Ivry, , 1997, but see also (Gibbon et al, 1997).…”

“…The measurement of tens or hundreds of milliseconds is important for coordination of muscles during movement (Hore, Wild, & Diener, 1991), while the measurement of multisecond durations is more commonly associated with learned behaviours such as social interaction or foraging (Brunner, Kacelnik, & Gibbon, 1992;Pyke, Pulliam, & Charnov, 1977). Time measurement has also been shown to have quite different properties at these two duration ranges.…”

Role of Myelination in the Development of a Uniform Olivocerebellar Conduction Time

“…It has been proposed that synchronous CS activity may facilitate the timing of muscle activation (Llinás 1991), and damage to the cerebellum or IO leads to a variety of motor symptoms, including action tremors, which may be related to the improperly timed activation of muscles (Adams and Victor 1993;Holmes 1939;Hore et al 1991;Soechting et al 1976). Moreover, the patterns of synchronous CS activity have been shown to change in relation to voluntary movements (Welsh et al 1995).…”