1963 Volume 66 Issue 1 Pages 24-34
The labyrinthine deviations of a certain subject proved by several clinical tests of the vestibulo- spinal reaction are considered to direct towards one constant side but they often direct towards each opposite side in upper extremities and in lower ones respectively. This phenomenon is called the dissociation of the vestibulo-spinal reactions. The authors investigated the dissociation between the stepping test and the blindfolded vertical writing test (Fukuda) using another test of the vestibulo-spinal reaction, the arm-tonus reaction (Wodak, Fischer) i.e. the lowering of each upper extremity stretched forwards and the deviation of the head, upper extremities and the trunk towards one side.
1. Generally the spontaneous deviation of the head, upper extremities and the trunk are directed towards the side of the impaired labyrinth, but, accompanied by the healing process of the disease, the direction of the deviation changed towards the opposite side i.e. towards the side of the unimpaired labyrinth. The former deviation must be an expression of the stage of disturbance while the latter one an expression of the stage of coordination according to Fukuda's theory.
2. The head, upper extremities and the trunk righted themselves from the deviated positions in this order. In stages of this healing process, the dissociation between the stepping deviation and the writing deviation was observed occasionally, i.e. the former deviated towards the side of the impaired labyrinth while the latter deviated towards the side of the unimpaired labyrinth.
3. In most clinical cases the positive arm-tonus reaction, especially the spontaneous lowering was observed only in the upper extremity of the same side as the impaired ear through the whole progress of the disease. However, the arm-tonus reaction induced by caloric stimulation which evoked an experimental eye nystagmus at first braught about a lowering of the upper extremity of the same side as the caloric stimulated ear, and after a while, at which an eye nystagmus almost ceased, the lowering of the upper extremity of the opposite side i.e. the side of the unstimulated ear was seen.
