Discussion:
This classification needs to include a general statement on multi-impairment and its effect on the functions and activities of the person. Dual sensory impairment or disability is a typical example of multi-impairment that is more than the sum of its components. Combination of visual and hearing impairment affects the personís activities different from the way single sensory impairments affect a personís activities. For example:
- loss of some hearing in one ear is not considered an impairment. However, if a visually impaired person loses hearing in one ear and thus loses auditory orientation, (s)he needs to learn orientation and mobility techniques of a deaf-blind person.
- if a deaf person loses peripheral visual field, his communication in groups of people is seriously affected, much more than communication of a hearing person.

Thus an additional chapter is needed:


CHAPTER ONE C - DUAL SENSORY FUNCTION LOSS (000-000)

A person with dual sensory function loss may use different types of techniques for different activities. The technique used is described based on the general use of different techniques by the visually impaired persons, by the hearing impaired persons and by persons with dual sensory impairement. The functional ability in each of the four main areas of daily functioning is assessed separately, preferably when the person is using appropriate techniques. If the person has not learned appropriate techniques, specific notice needs to be made on that inappropriate/ineffective techniques were used.

020 Vision in communication, technique used is that of
A: a sighted person
B: a person with low vision
C: a blind person
D: a deaf-blind person
021 Vision in orientation and mobility, technique used is of
A: a sighted person
B: a person with low vision
C: a blind person
D: a deaf-blind person
022 Vision in activities of daily life, technique used is of
A: a sighted person
B: a person with low vision
C: a blind person
D: a deaf-blind person
023 Vision in sustained near vision tasks, technique used is of
A: a sighted person
B: a person with low vision
C: a blind person
D: a deaf-blind person