Monaural Auditory Cue Affects the Process of Choosing the Initial Swing Leg in Gait Initiation

The authors investigated the effect of an auditory cue on the choice of the initial swing leg in gait initiation. Healthy humans initiated a gait in response to a monaural or binaural auditory cue. When the auditory cue was given in the ear ipsilateral to the preferred leg side, the participants consistently initiated their gait with the preferred leg. In the session in which the side of the monaural auditory cue was altered trial by trial randomly, the probability of initiating the gait with the nonpreferred leg increased when the auditory cue was given in the ear contralateral to the preferred leg side. The probability of choosing the nonpreferred leg did not increase significantly when the auditory cue was given in the ear contralateral to the preferred leg side in the session in which the auditory cue was constantly given in the ear contralateral to the preferred leg side. The reaction time of anticipatory postural adjustment was shortened, but the probability of choosing the nonpreferred leg was not significantly increased when the gait was initiated in response to a binaural auditory cue. An auditory cue in the ear contralateral to the preferred leg side weakens the preference for choosing the preferred leg as the initial swing leg in gait initiation when the side of the auditory cue is unpredictable.