[Peripheral vestibular damage causes impaired navigation tasks on memorized routes in humans].
OBJECTIVE
To investigate if a well-compensated unilateral peripheral vestibular hypofunction could interfere with navigation tasks on memorized routes in humans.


METHODS
After a complete otoneurological investigation, fifty labyrinthine-defective patients and fifty controls were invited to visually memorize three different routes (a triangle, a circle and a square) on a grey carpet and then to walk along them with eye closed clockwise and counter-clockwise (mental map navigation). The same test was then repeated with eye open (actual navigation) and again with eye closed (mental navigation). Execution time was recorded in each test. Corsi block test and a psychiatric questionnaire completed the neuropsychological examination.


RESULTS
Labyrinthine-defective patients showed higher levels of anxiety and depression and performed Corsi block test with more difficulties than controls. Patients spent more time than controls in the first and third session (eye closed). No difference was recorded between clockwise and counter-clockwise navigation tasks both in patients and in controls. Patients showed a greater improvement in the third navigation task than controls.


CONCLUSIONS
Walking on memorized routes in non-visual condition is impaired by a peripheral vestibular damage, even if patients are well compensated. This impairment could be due to a defect of the visuospatial short-term memory, as supported by Corsi block tests, but a residual sensorimotor impairment and/or an interference of psychological distress could not be definitively excluded.
Guidetti
G
G
Audiological and Vestibular Center of Azienda USL of Modena, Italy. guidetti.giorgio@policlinico.it
Monzani
D
D
Trebbi
M
M
Rovatti
V
V
D000328:Adult; D000368:Aged; D007758:Ear, Inner / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012720:Severity of Illness Index; D013037:Spatial Behavior; D015837:Vestibular Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D014796:Visual Perception