Walking performance of vestibular-defective patients before and after unilateral vestibular neurotomy.
The present study investigated goal-directed linear locomotion in nine Menière's patients before and after (1 week, 1 and 3 months) a curative unilateral vestibular neurotomy (UVN). Experiments were done using a 3D motion analysis system in subjects walking eyes open (EO) and eyes closed (EC) towards a real or memorized target, respectively. Locomotor pattern (velocity, step length, step frequency and walk ratio) and walking trajectory deviations were evaluated for normal and fast speeds of locomotion and compared to those recorded in 10 healthy subjects. Before UVN, patients showed no walking deviation but gait pattern changes characterized by slower walks compared to the controls, mainly due to step length and step frequency reductions for both visual conditions and locomotion speeds. In the acute stage after UVN, locomotor pattern impairments were significantly accentuated. On the other hand, patients showed strong walking deviations towards the lesioned side with EC. Opposite lateral deviation towards the intact side were observed with EO for normal speed only. Recovery from impaired locomotor pattern was achieved within 1 month for normal speed but remained uncompensated 3 months post-lesion for fast speed particularly in EC condition. Finally, the walking trajectory deviation towards the lesioned side in the dark was maintained up to 3 months after UVN. The results show that central processing of visual and vestibular cues contributes to an accurate locomotor pointing. They argue for an increased weight of visual reference frame on locomotor functions when vestibular function is unilaterally impaired.
Borel
Liliane
L
UMR 6149, Neurobiologie Intégrative et Adaptative, Université de Provence/CNRS, 52, Faculté de St. Jérôme, Case 361, 13397 Marseille Cedex 20, France. borel@up.univ-mrs.fr
Harlay
Françoise
F
Lopez
Christophe
C
Magnan
Jacques
J
Chays
André
A
Lacour
Michel
M
D000328:Adult; D001696:Biomechanical Phenomena; D003624:Darkness; D003714:Denervation; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008027:Light; D008124:Locomotion / Q000502:physiology; D008297:Male; D008575:Meniere Disease / Q000503:physiopathology / Q000601:surgery; D008875:Middle Aged; D019635:Neurosurgical Procedures; D004856:Postural Balance / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D015837:Vestibular Diseases / Q000503:physiopathology* / Q000601:surgery; D014725:Vestibular Nerve / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology; D016138:Walking / Q000502:physiology*