The PERCEPT programs address aspects of Visual Perception, including LSA's functional visual field series (PERFIELD and CENFIELD), as well as tasks which require integration of visual information and visual scanning, analysis and memory. Optometric scanning (OPTOMEX) calls for scanning arrays of letters or numbers for information in an efficient fashion, much as one would need to scan a schedule or chart. Immediate feedback is offered and it is possible for the individual to perform this exercise independently on a home computer. In Line Bisection (BISECT) the individual has to size up a stimulus and determine its middle. This must be done in a timely fashion: once the midpoint is moved and comes to rest, the decision is finalized.
Visual Memory (VISMEM) requires retention of a nonverbal stimulus array. With the computer one can place stimulus components and effectively engage in visual recall (not just recognition, as is the case with non-computerized visual memory tasks). In the PATTERNS exercise there is an implementation of the Audiovisual Integration Task (AVIT) in which the person has to recognize the equivalence of auditory sequences and visual patterns.
"This task is a computerized version of the classic neuropsychological "Line Bisection" procedure and is designed to detect spatial hemi-imperception. Extremely simple to comprehend, it is suitable even for severe cases. The rationale for this task is that if people are hemi-imperceptive, they will see less of the impaired side. Accordingly, they will displace the "middle" toward the intact side, i.e., toward the right for a left hemi- imperceptive. The lines are either horizontal or vertical and long (about 20 degrees of visual angle) or short (about 5 degrees of visual angle). The line is placed randomly on the screen and the starting position of the gap is randomly placed at one or the other end of the line. Feedback, an examiner-selected option, is available when using BISECT for training.
These tasks elicit scanning. In one format, arrays of letters (like the Hart charts used by optometrists for training accommodation) are scanned for the letter in a given column and row. In another format, the individual types the first and last letters in each line. Charts range to 10 x 10 letters. Feedback includes the efficiency and accuracy of responding.
An 8 by 8 array of homogeneous shapes ("Martians") is searched for one different shape (a "sleeping" Martian). Search times are recorded from when the display appears to when the ultimately successful response was initiated. This program is designed to detect differences in attention and responsiveness on the two sides of the visual field. It is particularly designed to identify those persons who have a spatial hemi-imperception which affects their ability to scan both sides of a display efficiently and, used in conjunction with SEARCH, it differentiates this skill from shape examination and matching. The display contains an intermediate level of information compared to REACT (one stimulus in an otherwise empty display) and SEARCH (an 8 x 8 array of heterogeneous shapes). This variation in information density enables one to differentiate hemi-inattention and hemi-imperception.
Based on a classic visual search task by Poppelreuter, this task requires the location of a target shape in an 8 x 8 array of different shapes. The shapes are abstract geometric patterns. Search time is recorded and analyzed by location. SEARCH for Shapes is informationally dense and designed to demand much attention to all areas of the display. It is a task which calls for many skills, ranging from visual inspection, short-term visual memory, uniform scanning on both sides of the display, to sustained attention and frustration tolerance.
VISMEM is a short-term memory storage task which does not involve explicitly verbal stimuli. Checkerboard displays are reproduced by key presses or using switches. The exercise focuses on visual, non-verbal memory. Persons with no keyboard skills can use this program via simple key presses or via switch inputs. You can choose simple or complex displays and increase the length of the series as improvement occurs. The computer displays one or more irregular patterns within a checkerboard. After the displays are studied, an opportunity is given to "paint" one of the displays on the screen by pressing arrow keys. The computer keeps a running count of your scores
HOWMANY requires response competency at the second milestone, namely a controlled number of repetitions of a single response. Switch or mouse presses can be used. HOW MANY requires response competency at milestone #2 (Controlled repetition of a response). This level of response competency is a precursor to training yes-no communication where one tap means "no" and two taps means "yes". The HOW MANY program presents a series of flashing squares or tones, or both, followed by an opportunity to tap out a corresponding number of times, e.g., hear three beeps, tap three times on the switch. An example would be: S = BEEP BEEP BEEP R = TAP TAP TAP In order to do the HOW MANY task, one must a) keep track of number b) stop responding when number is reached.
Here, a patterned response sequence must be produced in response to a model. Not only the number, but the timing of the responses is important. This task reflects competency at the third milestone of response competency. PATTERNS calls for the ability to repeat a patterned series of responses. This task requires memory for the pattern and the ability to execute it. It is the defining task for the third milestone of response competency. Because stimuli can be visual (light flashes) or auditory (beeps), the PATTERN procedure can be conducted as the AVIT (Auditory Visual Integration Task). Added to the requirements HOW MANY is the ability to control the timing of the response. For example: Stimulus = BEEP (PAUSE) BEEP BEEP Response = TAP (PAUSE) TAP TAP (not TAP TAP TAP) Appropriate pausing is now required. Visual and auditory stimuli can be selected.
The computer flashes a word and asks that it be typed in. The task speeds up as long as one can keep up, and slows down after errors. Word lists come with the program; custom word lists can be created with a text editor. The program is included as a brief visual memory exercise, but it also is useful for persons with deficits in attention, foveal perception, and verbal apraxia (difficulty planning and articulating words). The task offers feedback for visual imperception, reinforces attention and alertness, and exercises the typing and production of words. A "copy" mode is also an option.
This task was designed to diagnose foveal hemi-imperception using non-verbal materials. Following brain injury, lateralized visual hemi-imperception is not uncommon. If the central (perifoveal) visual fields are involved, reading and focused visual work may be impaired. The purpose of MATCH is to identify any possible lateralized impairment in the perifoveal fields.
Two detailed geometric figures are displayed one above the other. The patient has to decide whether the shapes are the same or whether they differ in some small way. Decision times are reported for left, right and both sides different.
INSPECT calls for the inspection of two nearly identical shapes to locate a small difference on either the left or right side of the shape. Like MATCH, it is an exercise which addresses central field hemi-imperception in a nonverbal manner.
The purpose of INSPECT is to offer practice in making discriminations in the central visual field, with feedback based on laterality. Some persons will have a lateralized hemi-imperception following an acquired brain injury. An important issue is the extent of visual involvement and, especially, the central (perifoveal) field. INSPECT is a simple form discrimination in which there is always a difference: the issue is which side is it on? The patient must be able to press the corresponding left and right sides of the mouse buttons.
A further level of complexity is offered with INSPECT: if the stimuli are reversed (black on white) the response keys are reversed. Since lateralized differential response often has an attentional component, the response differential may be exaggerated under these more complex conditions.
Error Detection in Texts is a paper-and-pencil proofreading exercise designed to assess attention and, especially, central hemi-field impairment, which is otherwise difficult to diagnose and can interfere with near point activities. This task has proven to be very sensitive to lateralized impairments of the central visual hemi-field. Part of the sensitivity derives from the fact that the individual is NOT required to read out loud, and, therefore, is induced to read quickly. This task is also useful to assess the ability to sustain an independent work effort, as well as to evaluate the ability to detect errors.
The purpose of JUMP is to provide eye-movement exercise in lateral scanning. It requires horizontal scanning from a starting location which the patient locates before initiating a trial. A trial consists of successive exposure of two stimuli, either (-) or (=), one at the left edge and one at the right edge of the screen. A masking symbol follows the exposure of each symbol to prevent afterimages. The exposure duration of the stimuli determines the scanning rate required. Subjects initiate each trial by pressing a key. They must then indicate whether the stimuli were the same, and may "pass" if unsure. The computer adjusts the exposure duration (hence, the scanning speed required) based on the patient's performance. Correct answers lead to faster trials, while errors and "passes" lead to slower ones. This self-adjusting procedure continues for five blocks of ten trials, in which time a patient has usually reached the limit of scanning ability. The printed output shows rate of improvement graphically at a glance.
This procedure is designed to diagnose and treat at least four basic functions of human visual information processing. They are: anchoring at the margin, scanning horizontally, identifying words within the perceptual span, and monitoring the periphery. Once problems have been diagnosed, SRWL can be used for rehabilitation. Word lists are presented in three different formats. In the first, lists of nine words across are presented on the screen. The patient reads lists from left to right and then from right to left. In the second, the patient reads words as they appear one at a time in the center of the screen. In the third, the patient reads words one at a time, but some of the words are unexpectedly placed off to the left or right on the screen.
Search-A-Word is a paper and pencil based task where the target stimuli are located on the left or right side of the display in equal numbers. Times to locate different words are recorded by the examiner. It is supplied in booklet form.