II.C.1: Physical Development (Including Vision and Hearing)
First let us consider the child's physical development. IDEA uses the term physical development, which includes vision and hearing. Often, the term sensori-motor development is used instead as it encompasses the child's sensory and motor systems.
The sensory system includes auditory, visual, tactile, proprioceptive or vestibular functioning. The child's auditory and visual functioning should always be evaluated before any other testing is initiated to rule out vision or hearing loss. If a child's visual or auditory modalities are compromised, then it stands to reason that other modalities will be impacted. Corrective procedures will provide the child with the opportunity to respond optimally to environmental demands and should ameliorate overall functioning.
There are several types of hearing impairments: conductive, sensorineural, or mixed. A conductive hearing loss occurs as the result of interference of sound passing between the external auditory canal and the inner ear because of damage to the external or middle ear. This type of loss is often the result of middle ear effusion of fluid from repeated episodes of otitis media (ear infections), and affects lower frequencies. Sensorineural loss is the result of damage to either the cochlear hair cells, the cochlea, the auditory nerve or the brain, which generally affecting higher frequencies of sound.
So, what is assessed? The minimal level of intensity of sound the child can hear. Trained personnel, generally audiologists, Ear Nose and Throat Specialists or speech language pathologists assess auditory functioning. They assess this by using one or more of the following approaches:
Since other professionals are responsible for assessing auditory functioning your role is more limited. You can however, familiarize yourself with the factors associated with hearing loss. The ABC's of deafness (Northern & Downs, 1991) include:
Assessment of visual functioning focuses on acuity and the use of visual fields. Vision specialists, optometrists and ophthalmologists are usually trained to perform visual assessments. In young children the Teller Acuity Cards can be used to estimate visual acuity. Visual Evoked Responses can be obtained by placing electrodes over the occipital cortex to detect disturbances of the visual pathway. When the child is older and can match or label, picture cards can be used. There are a number of these types of tests available, including the Snellen E charts. The New York Flashcards (or the Lighthouse Test) is preferred for use with preschool children with disabilities. The Lighthouse Test has cards with three different symbols, an apple, a house, and a umbrella representing visual acuities from 10/15 to 20/200.
In some cases, other professionals are trained to conduct vision screenings which may include tests such as the Lighthouse Test. However, if a visual acuity problem is detected in a screening, then the child should be referred to a specialist for more thorough testing. It is important that the child be tested for structural abnormalities in addition to a more intensive measure of acuity. Stangler, Huber, and Routh (1980) described behaviors suggestive of visual disorders including:
Vestibular, Tactile and Proprioceptive Modalities
Some definitions are in order:
Vestibular system: orientation of the head in space and is responsible for balance and posture
Tactile system: responsible for perception of touch, pressure, temperature and pain
Proprioceptive system: awareness of the body's position in space.
Each of these systems work together with visual and auditory functioning to organize all input to the senses. Children who demonstrate sensory dysfunctions often have difficulty with other developmental tasks. The functioning of these three systems are often assessed by occupational or physical therapists. Assessment measures include the Miller Assessment for Preschoolers (MAP) (Miller, 1982) and the Test of Sensory Functioning in Infants (DeGangi & Greenspan, 1989). Some of the developmental scales that will be discussed later in this module include items that assess functioning in these modalities.
Several areas of motor skills are generally included in an assessment. These are gross motor, fine motor and oral-motor skills. Gross motor skills refer to activities involving large muscles of the body and include rolling, crawling, walking and running. Fine motor skills involve the use of small muscles, particularly muscles of the arms and hands. Fine motor skills include reaching and grasping and releasing. Oral-motor skills involve the use of the lips, mouth, tongue, teeth and facial and jaw muscles. Assessment of oral-motor skills focuses on sucking, swallowing, biting and chewing.
Pediatric occupational and physical therapists are prepared to conduct assessments of motor skills. Increasingly, however, there is a shift toward more transdisciplinary approaches in assessment that underscore the need for all professionals to understand assessments across all developmental domains. This module will not prepare you sufficiently for this new role. You are encouraged to do further reading in this area and observe occupational or physical therapists conducting assessments. Examples of instruments used to assess motoric functioning include: