(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.