The Cognitive Assessment of Deaf and Hard of Hearing Children in Ireland: Best Practice for Educational Psychologists

A recent publication from the NCSE* (The Education of Deaf and Hard of Hearing Children in Ireland, 2011, p65) recommended that “The National Educational Psychological service should work towards a psychological service being available with a sufficient level of competency in ISL to administer psychological assessments and to communicate with parents and children whose preferred mode of communication is through ISL”. The research undertaken was to investigate the challenges that arise when cognitively assessing such children and to test assessments tools to try develop an awareness of best practice in the field (in line with NEPS draft recommendations).

The Wechsler Intelligence Scale for Children fourth edition (WISC-IV UK) was administered through ISL including the Verbal Comprehension Index, Working Memory Index and Processing Speed along with the traditional format of assessing Fluid Intelligence (Perceptual Reasoning) to establish a Full Scale I.Q. The Wechsler Non-Verbal Intelligence Scale of Ability, which requires no language input, was then administered to the same students (N=33)
In theory, both tests assert that they are assessing “Intelligence” or cognitive ability “g” and should produce similar if not identical I.Q scores. The research aimed to analyse these scores and see if they are consistent across the sample and examine any irregularities that might arise from the data.

Results showed that there was a very significant difference in the I.Q scores of the WNV and the WISC IV (p<.0001) and that there was a very large negative “effect size” for using ISL. Results would suggest that administering one of the most commonly used I.Q tests (WISC IV) actually discriminates against ISL users and is therefore contradictory towards the NCSE policy paper.

Issues that arose during the tests when using ISL interpreters for ISL users include translation of concepts that are not evident in ISL, the use of finger spelling and the issue of “back translation” whereby what is signed is not necessarily the same as what is spoken. This raises issues around the understatement of cognitive scores amongst the Deaf population and the difficulties that arise for educational psychologists in areas such as Working Memory, Verbal Comprehension Testing and the challenges of BICS and CALP.