Deaf: Generally, the term "deaf" refers to those who are unable to hear well enough to rely on their hearing and use it as a means of processing information. For more information on this term, please visit the National Association for the Deaf Web
site.

Deaf-Blind: A combined loss of vision and hearing.

Depakene: Also known as Valproic acid. An anti-epileptic seizure medication.

Development: The process of growth and learning during which a child acquires skills and abilities.

Developmental disability: A disability or impairment beginning in infancy or childhood which may be expected to continue
indefinitely and which causes a substantial disability. Such conditions include pervasive developmental disorders,
autism, cerebral palsy, and mental retardation.

Developmental milestone: A developmental goal such as sitting or using two word phrases that functions as a measurement of developmental progress over time.

Developmental sequence: The normal progression of motor skills, including all areas such as fine motor, gross motor, personal and social.

Diabetes: Usually meaning diabetes mellitus, a chronic disorder characterized by insufficient insulin and improper metabolism of body glucose.

Digit: Toe or finger

Dilantin: Phenytoin. An anti epileptic seizure medication.

Diplegia: A type of cerebral palsy in which spasticity primarily affects the legs.

Diplopia: Double vision.

Disability: As defined in the Americans with Disabilities Act: (A) a physical or mental impairment that substantially limits one or more major life activities, e.g., seeing hearing, speaking, walking, working, learning, breathing, performing manual tasks,
and caring for one's self or (B) a record of such an impairment or (C) being regarded as having such an impairment.

Discretionary trust: A trust in which the trustee (the person responsible for governing the trust) has the authority to use or not use the trust funds for any purpose, as long as funds are expended only for the beneficiary.

Dispute resolution procedures: The procedure established by law and regulation for the fair resolution of disputes regarding a child's special education.

Domam-Delacato Method : See Patterning.

Dopa-responsive Dystronia (DRD): This genetic disorder first appears in young children (ages 2-6). It is characterized usually by the onset of dystonia in a limb (usually a leg) affecting walking and over time spreading to involve other limbs.

Dorsal Rhizotomy: See Selective Dorsal Rhizotomy.

Dorsiflexion: Upward motion of the foot toward the body.

Drooling: It is generally accepted that drooling occurs because of a defect in the oral or voluntary phase of swallowing, resulting in an overflow of secretions which builds up in the front of the mouth (Shott et al. 1989).

Dysarthria: Impaired articulation due to problems in muscle control.

Dyskinesia: A general term for involuntary movements.

Dyspraxia: Difficulty planning movements and putting them into sequence.

Dystocia: Difficult labor.

Dystonia: The term used to describe an illness dominated by involuntary spasms and muscle contractions that induce abnormal movements and postures. Such dystonic spasms may affect one part of the body, such as the eyes, neck or a limb;
a larger region, such as the neck and arms; or the whole body. Slow, rhythmic, twisting movements. Dystonia is a
neurological disorder of the brain characterized by sustained muscle contractions which frequently causes twisting
or repetitive movements of a body part (eyelids, tongue, hand, limb, neck, trunk, etc.) or abnormal postures. Also, a
tremor may accompany these symptoms. Symptoms are often exacerbated by active voluntary movements.