Pediatric Primary Care
Screenings: Hearing & Vision
Perspective on Screenings: Hearing & Vision.
Screening in very young patients for vision and hearing anomalies may be accomplished by primary health-care providers but is often carried out by ancillary personnel or referral. Screening is problematic, since some children may have normal hearing and vision but appear disconnected from the brain's higher interpretative centers. A number of disorders are complicated by mixed hearing and vision results, e.g. children on the autistic spectrum, with genetic or inherited disorders, etc. Referral results when data are conflicted.
Problem Identification
Very young children may present with convoluted presenting complaints. Parents themselves may give a conflicted and confused history for their child. Even adults, with sudden onset stroke symptoms, may not be able to describe what has happened to create their current wellness situation. The health-care provider team assessing any child must determine whether a problem is present, initiate an appropriate screening to verify, and refer as appropriate.
Unclear Etiology and Clinical Findings in Children Suspicious for Hearing or Vision Anomalies
Children develop in the womb for those nine months of pregnancy. That gestation period may be uneventful or be complicated by things like family genetics, rubella, zika, birth trauma, etc. A newborn will be unable to explain problems that were never problems in the womb. An infant with invisible problems may be asymptomatic and appear apparently normal for years. Hearing loss and many vision problems may be unrecognized because significant players in the child's life do not recognize anomalies in child development or perception.
Generic Normal Development
A child presents to mom and dad as a blank sheet. That sheet fills with time. Behaviorists explain that the child's behavior is the sum total of all past events inscribed on that blank sheet. However, there has to be ink in the pen and that the paper has to be able to receive what is written. Cognitive scientists of the last seventy years have suggested that speech and language develop in response to a genetic-based sound replication circuit or echo cycle that is inherent to humankind. Language development is impaired when a child develops without that speech stimulation and replication. That is, a hearing loss or apparent blindness may not be deafness or blindness per se, but rather a failure in the nervous system to connect the peripheral sensory nervous system with higher centers of processing.
Vision provides added redundancy to the sound stream's string of phonemes. Visual awareness of surroundings is impaired when things are not seen with sufficient clarity to permit discernment of similar shaped and colored objects. Without basic auditory and visual acuity stimulation, a child will not develop normal speech and language or normal analytic acuity using visual cues. Yet, the child may appear normal with ears that are shaped appropriately but that are unable to hear. Eyes may be baby blue, appear to focus on faces, but be unable to discern visual objects and people.
Screenings: Hearing & Vision
Behavioral screening activities to determine auditory and visual function help a health care provider determine whether the two senses are intact. Screening allows the practitioner to understand if speech and language delay or visual acuity relates to sensory perception versus processing problems within the central nervous system. Behavioral or electronic screening may be used. Behavioral screening relies on pairing a stimulus-response with reinforcement and the monitoring of that stimulus-response. In the case of both hearing and vision, response to impulse noise or light flashes do give information about perception, since intensity can be controlled along with frequency. Frequency and threshold determination is possible, but a floor for function level may be chosen arbitrarily with a child passing or failing if the stimulus-response behavior is noted. Operant technology gadgetry using toys and interesting objects continue to be employed where a positive reinforcement is tied to that stimulus-response, but test paradigms require a clinician capable of reading human behavior.
Passive screening with electro-physiologic monitoring requires no such judgment. With the advent of computerized monitoring of auditory (ABR) and visual (VBR) systems using scalp electrodes in an awake or sleeping youngster, a clinician can objectively determine the integrity of sound transmission via auditory hair cells, auditory nerve, brainstem, and auditory cortex or light transmission via retina, optic nerve, brainstem, and visual cortex. Many practitioners are aware of screening programs in newborn units across this country using this technology. Similarly, acoustic reflex and otoacoustic emission studies may obtain similar information, but findings are limited to hearing "below" the brainstem level. That is, the central nervous system is not screened as with the ABR or VBR. Similar peripheral and central monitoring systems exist for both auditory and visual modalities.
Using Screening Results
Childrens hearing, vision, and speech and language needs are not defined by screening. Screening results are data obtained at points in time. Children at risk for familial developmental problems with hearing or vision may pass an early screening but develop significant problems later in their development. Family or disease history for a given youngster will dictate whether a primary care provider determines whether screening procedures should be replicated at a later time, periodically, or that patient be referred for audiology-otolaryngology-ophthalmologic services as a result of screening failure.
Normalcy
With today's electrophysiological instrumentation, where questions are present in those first months of life, definitive answers are possible. A deaf child with early identification can have normal speech and language with a cochlear implant. With research going on at this time, similar prosthetic advances may bring vision to those who fail vision screening in the future.