Dr.H.S.Frenkel was medical superintendent of the Sanatorium 'Freihof' in switzerland towards the end of last centuary. He made a special study of tabes dorsalis and devised a method of treating ataxia, which is a prominent symptom of the disease, by means of systemic and graduated exercises. Since then his method has been used to treat incoordination which results from many other diseases, e.g. disseminated sclerosis.
He aimed at establishing the voluntary control of movement by the use of any part of sensory mechanisn which remains intact, notably sight, sound, touch, to compensate for the loss of kineasthetic sensation. The process of learning this alternative methoad of control is similar to that required to learn any new exercise, the essentials being-
a-concentration of attention
The ultimate aim is to establish the control of movement so that patient is able and confident in his ability to carry out these activities which are essential for independence in every day life.
1-The patient is positioned and suitably clothed so that he can see the limbs throughout.
2-A concise explanation and demonstration of exercise is given before movement is attempted, to give patient a clear mental picture of it.
3-The patient must give his full attention to the performance of exercise to make movement smooth and accurate.
4-The speed of movement is dictated by physiotherapist by means of rthymic counting, movement of her hand or the use of suitable music.
5-The range of movement is indicated by making the spot on which the foot and hand is to be placed.
6-The exercise is repeated many times until it is perfect and easy. It is tehn disccarded and a more difficult one is substituted.
7-All these exercises are very tiring at first, frequent rest periods must be allowed. The patient retains little of no ability to recognize fatigue, but it is usually indicated by a deterioration in the quality of movement, or by a rise in pulse rate.
Frenkel exercises are also effective in Cerebellar ataxia ( which has also been discussed else where in this forum and you may have a look over that).
For more detail have a look over.
Principles of exercise Therapy, 4th edition by M.Dina Gardiner
Physical Rehabilitation, Assessment and treatment, 4th Edition By O'Sullivan and Schmitz