(a) An individual has a functional disability if the individual has a severe, chronic disability that:
(1) is attributable to a mental or physical impairment or a combination of mental and physical impairments, including a head injury;
(2) is likely to continue indefinitely;
(3) results in substantial functional limitations in at least three of the following areas of major life activity:
(i) self-care;
(ii) receptive and expressive language;
(iii) learning;
(iv) mobility;
(v) self-direction;
(vi) capacity for independent living; and
(vii) economic self-sufficiency; and
(4) reflects the individual’s need for a combination and sequence of special interdisciplinary or generic care, treatment, or other services that are:
(i) lifelong or of extended duration; and
(ii) individually planned and coordinated.
(b) An individual has a developmental disability if the individual has a functional disability that is manifested before the individual attains the age of 22 years.