In the 1970’s Paula Tallal showed that children with Specific Language Impairment had difficulty with the temporal ordering of auditory stimuli. Since then many other researchers have found this to be an important component to consider for children and adults with dyslexia, SLI, aphasia and other reading, speech and phonological deficits.
Temporal Order Judgment (TOJ) simply means that two signals are presented and the person being tested is asked to identify “which came first?” The gap between the signals, known as the inter stimulus interval (ISI) is altered so that the ISI becomes smaller with correct responses or alternatively it is delivered in a random manner.
It is thought that the ability to perceive ordered signals in this way is a function of the magnocellular system in the brain. This system tracks moving signals and it is thought that a deficit in the function of this, an M-cell deficit, will cause a masking effect so that the order of the signals cannot be detected when they are close together. There is direct evidence in the brain for this type of deficit in at least some types of dyslexia.
Many researchers including Laasonen* et al. have also found that a challenge with the ordering of signals extends across sensory domains and can be found in the auditory, visual and tactile senses.
Testing TOJ is therefore an important component when assessing children with speech and language, listening, and reading deficits. Using measures such as TOJ allows you to consider whether more fundamental auditory processing is impaired. This is an underpinning level of temporal processing on which phonological awareness is built.
The Test of Auditory and Visual Skills (TAVS) allows for the screening of auditory and visual temporal order. In the auditory TOJ task, two pure tone signals of equal pitch are delivered to the left and right ear. The question is “which ear was the first sound in?” With the visual TOJ task, two red LED’s on the TAVS panel deliver a flash. The response is to press the button where the first sound or light flash came. Correct answers mean the signals are delivered with a smaller ISI until we reach the point where errors are made. Incorrect responses simply mean that the signals become further apart. In this way a threshold or best value is reached a number of times.
With the TOJ task only taking 3 minutes and relevant norms available from age 5 upwards, this is a simple to use and understand tool that can give vital information at a fundamental level in terms of auditory and visual processing.
While this type of test does not seek to diagnose dyslexia or any other condition, it plays an important role in pre and post testing when using The Listening Program®, inTime, or any other intervention designed to improve learning, listening and attention. TAVS offers a range of auditory and visual screening areas which are a powerful way to assess sensory processing at a foundational level.
If you are a professional in the field and would like to learn more about training to become qualified in the administration of TAVS please click here or call Advanced Brain Technologies at 801.622.5676
* Laasonen, M., Service, E. and Virsu, V. (2001) Temporal order and processing acuity of visual, auditory and tactile perception in developmentally dyslexic young adults. Cognitive, Affective and Behavioural Neuroscience, 2001. Vol. 1 (4), 394-410