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Introduction
There currently does not exist a psychological test that will predict how well a visually impaired individual will be able to orient himself to objects in the environment. This task is critical for the independent travel needs of people who are blind. A test that will predict performance in this area will be of value in assessing the potential of individuals to orient themselves in new environments.
Relevant Literature
Orientation to the environment
occurs when an individual has achieved awareness of self-to- object relationships,
and object-to-object relationships (Bentzen 1995, Long 1995). Once oriented,
the individual is able to locate both nearby and distant objects. An individual
gains such orientation by using search strategies to establish relationships.
Hill et al (1993) have identified various strategies used by blind persons
to search unfamiliar space. It is clear that some individuals use efficient
and effective search patterns while others use haphazard and ineffective
methods. Essential skills necessary to establish and maintain orientation
include form recognition, memory for shapes, spatial location, and psychomotor
problem solving. To date there have not been conclusive tests that predict
the ability to establish spatial relationships without sight. The Tactual
Performance Test using the Sequin-Goddard Form board and administered according
to Halstead's 1947 procedures (Spreen and Strauss, 1991) serves to evaluate
several of the skills that make up spatial orientation. Data from this
test has not however been correlated with independent mobility. Development
of a test that correlates positively with spatial orientation would provide
a useful tool to identify blind and/or visually impaired persons who may
have difficulty with orientation tasks. This would enable alternative learning
strategies to be developed to assist these individuals.
Method
The Tactual Performance
Test using the Sequin-Goddard Form board is a test which holds the potential
to measure a person's ability to organize space. It is used to assess tactile
form recognition, memory for shapes, spatial location, and psychomotor
problem solving. While it has been designed for sighted persons, it can
easily be modified for persons who are blind since it is intended to be
administered to people wearing blindfolds and requires a subject to manipulate
assorted shapes by touch.
The test has several steps to it. The subject is placed in front of a small wooden form board that is made of common shapes that fit into puzzle like openings. While being timed, the subject is asked to place each object into the form board with one hand. The subject is next asked to repeat the process with the other hand. Next the subject is allowed to use both hands to again complete the puzzle. Now completely familiar with the forms and the openings that they fit into, the board is turned 90 degrees and the subject is asked to place the pieces into the openings once again. Finally the subject is told to ask for each piece by name and place it on the back side of the board where there are no cut outs. A series of scores are derived from these exercises that are an indication of spatial ability.
The subject is next taken to an in vivo test area which is actually a large open room that contains a 17 foot by 17 foot area that is cordoned off by way of rope that is taped to the floor. Within the roped area are four common objects: a bag, chair, waste paper basket, and a box. The subject is given 5-7 minutes to explore the area while using a cane. No attempt is made to provide the subject with an exploration strategy. Instead the test administrator observes and marks down the type of exploration system that is used (grid, perimeter, reference point, or non-systematic). The objects are removed and the subject is next asked to place the objects back to their previous locations within the roped off area. A record is kept regarding accuracy and length of time to replace the objects. The subject is then asked to use a laser pointer to point to the locations of the objects. Finally, the subject is moved to a position 90 degrees from the original starting point and asked to once again place the object down in their original locations. Again a record is kept of accuracy and length of time to replace the objects.
The purpose of the two tasks is to determine if performance on the form board correlates with performance in the large environment (invivo test). It was hypothized that individuals who are fast and accurate on the small form board will also exhibit good spatial orientation in the larger environment.
Results
The correlation coefficient
between performance on the small form board and the in vivo board was a
moderate + .52. This indicates a low but positive correlation between the
two tasks. Prediction of actual spatial abilities from the form board test
therefore can not be relied upon to provide an accurate prediction of performance
in the actual travel environment.
Conclusion
While there is a positive
relationship between the two tests, the relationship is not strong enough
to allow predictions of spatial abilities. This study was based upon the
results of only 20 individuals. It may be that variations between the subjects
were greater than the variations measured by the test data. Several of
the subjects had multiple impairments that affected their performance on
the in vivo task. Therefore more data must be collected with subject that
have equal motor abilities.
Bibliography
Bentzen, B. (In progress).
(Blasch, Wiener, & Welsh, Eds.) Orientation aids, Foundations of Orientation
and Mobility, American Foundation for the Blind. New York, N.Y.: AFB Press.
Hill, E.W., Rieser, J.J.,
Hill, M.M., Halpin, J. (1993). How persons with visual impairments explore
novel spaces: Strategies of good and poor performers, Journal of Visual
Impairment and Blindness. 87 (8).
Long, R.& Hill, E.W.
(In progress).(Blasch, Wiener, & Welsh, Eds.) Spatial orientation and
cognitive strategies for wayfinding and decision making, Foundations of
Orientation and Mobility, American Foundation for the Blind. New York,
N.Y.: AFB Press.
Spreen, O. & Strauss,
E. (1991). A compendium of neuropsychological tests: Administration, norms,
and commentary. (pp. 343-356), New York, N.Y: Oxford University Press.