Università degli Studi di Milano   Archivio Istituzionale della Ricerca
Please use this identifier to cite or link to this item: http://hdl.handle.net/2434/6646

Title: Coupling of hand and foot voluntary oscillations in patients suffering cerebellar ataxia : different effect of lateral or medial lesions on coordination
Authors: CAVALLARI, PAOLO (Last author)
CERRI, GABRIELLA (First author)
ESPOSTI, ROBERTO PAOLO (Second author)
Abstract: Motor coordination has been investigated in seven ataxic patients who underwent surgery of the cerebellar hemisphere (4) or of the vermis-paravermis region (3). Subjects, tested ipsilaterally to the lesion, were asked to couple in-phase rhythmic oscillations of the prone hand and the ipsilateral foot for at least 10 s. The oscillation frequency, paced by a metronome, ranged 0.8-3 Hz. Hand and foot angular displacements were measured by a potentiometric technique; EMG from Extensor Carpi Radialis and Tibialis Anterior was recorded by surface electrodes. The phase-relations between the hand and foot movements, as well as between the onsets of motor commands, were calculated. For each of the limbs the frequency-response curve was estimated by plotting the mean phase values between the onset of the motor command and the onset of the related movement. The experiment was repeated with the same schedule after a strong artificial increase of the hand inertial momentum (15 g m(2)). In the unloaded condition, all patients failed to achieve a hand-foot synchrony (0 degrees ), the hand movement showing a net phase-lag. In four hemispheric and one vermian patients (group 1) this lag progressively grew with frequency up to 110 degrees , in the other two vermian patients (group 2) the hand lag kept almost constant ( approximately 45 degrees ). Group 1 subjects were unable to adequate the delay between the motor commands to the increase in frequency, as instead did group 2 subjects, although this was insufficient to produce movement synchrony. Subjects reacted to hand loading with different strategies. In group 1, due to the net increase of hand inertia, movement synchrony required a strong advance of the hand motor command. Patients succeeded in this, but because of their inability to compensate for changes in frequency, they still produced a progressive lag between movements. In group 2, loading strongly increased the hand dynamic stiffness while it slightly lowered that of the foot, resulting in a rather small difference between mechanical properties of the limbs. Thus, compensation required only a slight anticipatory activation of the hand motor command. Patients failed to do so, however they were able to adjust the command delay to the required frequency and produced a constant hand lag. Their main motor handicap was found to to be the incapability of judging the hand lag as a lack of synchrony. These results seems to indicate that the cerebellum must be involved both in measuring the time difference between hand and foot movements and in weighting this delay in function of the oscillation frequency. These two processes may be confined to the vermis-paravermis region and to the hemisphere, respectively.
Keywords: Associated movements ; coordination ; motor control ; cerebellum ; human
MIUR subjects: BIO/09 - Fisiologia
Publication date: 2005
Digital Object Identifier (DOI): 10.1016/S0079-6123(04)48019-4
Citation: Coupling of hand and foot voluntary oscillations in patients suffering cerebellar ataxia : different effect of lateral or medial lesions on coordination / G. Cerri, R. Esposti, M. Locatelli, P. Cavallari. - In: Progress in brain research. - ISSN 0079-6123. - ISSN 1875-7855. - 148(2005), pp. 227-241.
Pubmed identifier: 15661194
ISI identifier: 000226746900019
Scopus identifier: 12344263552
Type: Article (author)

Files in This Item:

There are no files associated with this item.


SFX Query


Items in AIR are protected by copyright, with all rights reserved, unless otherwise indicated.


Share this record with your
favourite social network:

Del.icio.us

Citeulike

Connotea

Facebook

Stumble it!

reddit

mendeley


 

  Browser supportati Firefox 3+, Internet Explorer 7+, Google Chrome, Safari

ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software
CINECA