An apparatus for making combined vestibular and somatosensory function assessments of a user of the apparatus, comprising: a portable base unit comprising: a fixed platform; a rotatable platform being at least partially rotatable freely about a horizontal axis of rotation without the aid of any external drive; said rotation being carried out only by the force of the ankle movement of a user standing on said platform; in use, a user stands on the portable base unit in an even weight bearing stance with a first foot placed on the fixed platform and the other foot placed on the rotatable platform such that a long axis of the other foot is aligned with the axis of rotation for the rotatable platform; an adjustable stopping mechanism configured to adjust a maximal angle of rotation for the rotatable platform with respect to a horizontal plane to which the rotatable platform can be rotated by the user of the apparatus; and a controller configured to control various discrete stopping positions of the rotatable platform by controlling the adjustable stopping mechanism to selectively adjust the extent to which the rotatable platform can be rotated by the user by one of a plurality of discrete measurable amounts; a visual occlusion headset worn by the user, the headset comprising a device configured to record a vestibular function response of the user associated with a vestibular function test, wherein the visual occlusion headset comprises a sensing device configured to sense a user response following an adjustment made by the adjustable stopping mechanism, and wherein the sensing device (14b comprises an eye tracker having one or more sensors configured to determine a predefined visual response effected by the user, the predefined visual response being representative of the user's perception of the extent of the rotation of the rotatable platform following an adjustment made by the adjustable stopping mechanism, wherein the controller is further configured to receive the predefined visual response from the visual occlusion headset and to utilise it to perform ankle movement extent discrimination assessment of the user as a somatosensory function assessment. a portable base unit comprising: a fixed platform; a rotatable platform being at least partially rotatable freely about a horizontal axis of rotation without the aid of any external drive; said rotation being carried out only by the force of the ankle movement of a user standing on said platform; in use, a user stands on the portable base unit in an even weight bearing stance with a first foot placed on the fixed platform and the other foot placed on the rotatable platform such that a long axis of the other foot is aligned with the axis of rotation for the rotatable platform; an adjustable stopping mechanism configured to adjust a maximal angle of rotation for the rotatable platform with respect to a horizontal plane to which the rotatable platform can be rotated by the user of the apparatus; and a controller configured to control various discrete stopping positions of the rotatable platform by controlling the adjustable stopping mechanism to selectively adjust the extent to which the rotatable platform can be rotated by the user by one of a plurality of discrete measurable amounts; a fixed platform; a rotatable platform being at least partially rotatable freely about a horizontal axis of rotation without the aid of any external drive; said rotation being carried out only by the force of the ankle movement of a user standing on said platform; in use, a user stands on the portable base unit in an even weight bearing stance with a first foot placed on the fixed platform and the other foot placed on the rotatable platform such that a long axis of the other foot is aligned with the axis of rotation for the rotatable platform; an adjustable stopping mechanism configured to adjust a maximal angle of rotation for the rotatable platform with respect to a horizontal plane to which the rotatable platform can be rotated by the user of the apparatus; and a controller configured to control various discrete stopping positions of the rotatable platform by controlling the adjustable stopping mechanism to selectively adjust the extent to which the rotatable platform can be rotated by the user by one of a plurality of discrete measurable amounts; a visual occlusion headset worn by the user, the headset comprising a device configured to record a vestibular function response of the user associated with a vestibular function test, wherein the visual occlusion headset comprises a sensing device configured to sense a user response following an adjustment made by the adjustable stopping mechanism, and wherein the sensing device (14b comprises an eye tracker having one or more sensors configured to determine a predefined visual response effected by the user, the predefined visual response being representative of the user's perception of the extent of the rotation of the rotatable platform following an adjustment made by the adjustable stopping mechanism, wherein the controller is further configured to receive the predefined visual response from the visual occlusion headset and to utilise it to perform ankle movement extent discrimination assessment of the user as a somatosensory function assessment.