Benefit of Early Fitting and Behavior Modification Training with a Voluntary Closing Terminal Device


Developmental literature reveals that as growing organisms, human beings generally find their hands before they are able to speak.1-2 The process of learning both gross and fine motor coordination is one of natural positive reinforcement. Prior to an infant's developing language to represent experiences symbolically, the child learns motorically that hands are an extension of oneself which allow one to bring stimuli closer to one's sensory receptors. In the environment of most infants, stimuli attained manually have a reinforcing quality that results in pleasurable experiences and increases the chances of such behavior happening again. It is within this conceptual framework that infants as young as 6 months of age who have congenital upper-limb amputation are being fitted with a prosthesis with a voluntary closing terminal device. Theoretically, such a procedure should enhance early gross motor development and learning and should increase the sense of integrated body image at preverbal and early verbal stages.

Subject and Procedure

Travis first came to the University of Miami Pediatric Amputee Clinic at 5 months of age. He has congenital transverse deficiency of the left arm just below the elbow. Clinical interview revealed the patient to be the second child of college educated parents. He has an older brother, 3 years of age. Travis weighed 7 pounds 8 ounces at birth. His delivery was normal; however, just after birth he developed pneumonia secondary to fluid intake and experienced an episode of bradycardia. At 5 months of age, Travis presented as a cooperative, curious, responsive infant with a normal attention span and activity level.

In Phase I of the treatment, he was fitted with a prosthesis with a voluntary closing terminal device when 6 months 15 days of age. No occupational therapy was provided, nor any behavioral modification program to ensure effective use of the prosthesis. After an opportunity to discover use of the device in a normal, serendipitous fashion, a behavioral analysis of the patient's use of the prosthesis was performed at 7 months 29 days. Formal testing included the Bayley Scales of Infant Development.3 This test consists of a series of normed age-appropriate tasks for children between the ages of 2 to 30 months. Tasks test both language and cognitive developmental skills as well as motor skills. A Mental and Motor Development Index can then be derived to compare the child being tested to the performance of other children of similar age.

After testing, Phase II began. A behavior modification protocol was initiated that ensured a consistent shaping of wearing behavior on the infant's part, beginning at 20 minutes twice a day and increasing over the span of five weeks to two hours twice a day. Parents were asked to record the length of time as well as the specific times of day that the infant wore the prosthesis. Additionally, they noted any behavioral factors that might influence Travis' performance, e.g. teething, a cold, or wearing after a particularly long nap. Occupational therapy was instituted to specify for the parents the kind of activities for which Travis was to be encouraged to use his prosthesis. Occupational therapy and the behavioral shaping program allowed for intervention that provided the patient with a consistent opportunity for use of the prosthesis with consistent motoric feedback. At 9 months 7 days of age, Travis was again administered age-appropriate tasks from the Bayley Scales and another behavioral analysis was performed.

Phase III terminated the formal behavioral record keeping. Parents were encouraged to allow Travis to wear his prosthesis a minimum of two hours twice a day and gradually allow more time at each wearing as he could tolerate. A follow-up behavioral analysis and testing using the Bayley Scales was administered 15 months later, when the child was 24 months 5 days old to determine any long-term effects of the behavioral shaping and occupational therapy programs.


At the end of the first phase of fitting, with no occupational therapy or behavior modification program, the behavioral analysis revealed that Travis was not crawling nor was he incorporating his prosthesis into daily activities (Table 1 ). In fact, when wearing the prosthesis he often held it slightly behind him, apparently both out of sight and conscious awareness. The Bayley Scales indicated that he was functioning with a Mental Index of 119, while his Motor Index was 77 (Table 2 ). Mean scores on the Bayley are 100 for both Mental and Motor Indices, with a standard deviation of 16 points. Travis' discrepancy between indices was significant at the .001 level. His mental functioning was equivalent to an infant of 10.1 months of age, but his motor functioning was at the level of a 6.9 month old.

After training with an occupational therapist and five weeks of a behavioral shaping program designed by a clinical psychologist and instituted with the parents, the behavioral analysis revealed major changes. Travis now used his prosthesis to assist himself in pulling to sitting or standing positions. He had begun to crawl using the prosthesis, was incorporating it for balance in early walking stages, and for pushing, unwrapping, and stabilizing himself ('liable 1). Testing results on the Bayley revealed a Mental Index of 126 (equivalent to a 12.4 month old) and a Motor Index of 96 (equivalent to a 8.6 month old). While a discrepancy still existed between mental and motor functioning, Travis had gained 19 points on his Motor Index in five weeks. This was a gain greater than one standard deviation and is significant at the .05 level (Table 2 ).

Phase III testing and analysis, approximately one year later, revealed longterm effects of occupational therapy and behavioral shaping. Behavioral analysis revealed the patient to be engaging in age-appropriate indoor and outdoor activities (Table 1 ). Testing with the Bayley Scales resulted in a Mental Index of 101 revealing no significant difference between cognitive and motor development (Table 2 ). Translating the Mental and Motor Indices into standard norms, Travis was operating cognitively at the level of a 23.4 month old and motorically at the level of a 25.8 month old.

Discussion and Conclusions

Results of both behavioral analyses and formal testing scores indicate that merely fitting a young infant with an active prosthesis is not sufficient to ensure consistent opportunity and reinforcing motor feedback that will result in an increase in use of the device and simultaneous motor learning. Given occupational therapy and a behavior modification program, however, utilization of the prosthesis can be increased significantly. This can result in major development of gross and fine motor coordination skills.

The rate of motor learning can be enhanced. A significant discrepancy between cognitive and performance capacities as measured by age-normed testing can be reduced (Fig. 1 ). The rate of change appears to be influenced by both the parents' and the child's increased attention to the wearing of the prosthesis that a behavioral shaping program requires. Parents become more attuned to providing optimum timing and reinforcement to the child for wearing the prosthesis as a result of charting and other record keeping. Additionally, specific training with an occupational therapist assists the parents in providing the most appropriate activities that will stimulate gross and fine motor development suitable for the child's age.

Both occupational therapy and behavior modification programs need not be extensive. A five-week formal intervention period resulted in continued gains on a long-term basis a year after the intervention was suspended. Parents and child continued to exhibit awareness of a) consistent use of the prosthesis, and b) appropriate activities that allowed for success to build upon success and thereby expand the child's repertoire of motor activities in which the prosthesis could be used. While the rate of increase in motor learning slowed after the first year, it is significant to note that both mental and motor indices on formal testing revealed the patient to be operating on the average of nondisabled toddlers in his age group (Fig. 1) .

Early fitting of an active prosthesis can result in enhanced gross motor development and increased learning capacity. Early fitting, however, is a necessary but insufficient intervention in and of itself. A team approach involving an occupational therapist to assist parents in providing the child with activities that will result in specific successful motor feedback is essential. Additionally, a behavior specialist, who can design and institute a behavioral shaping program, will maximize consistent opportunities for employing learning strategies developed by the occupational therapist.

*University of Miami Rehabilitation Psychology Department, 1611 NW 12th Avenue Miami, FL 33136.


  1. Bandura A: Principles of Behavior Modification. New York: Holt, Rinehart and Winston, Inc., 1969.
  2. Rogers D: Child Psychology. Belmont, CA: Brooks/Cole Publishing Co., 1969.
  3. Bayley N: Bayley Scales of Infant Development. New York: The Psychological Corporation, 1969.