Score Discrepancy Between Verbal IQ and Performance IQ
By Inderbir Kaur Sandhu, Ph.D
Q: Can you please explain the scores discrepancy. If its only says clinically significant
1. VIQ > PIQ
2. PIQ > VIQ
3. If PSI and working memory both in low range but VIQ and PIQ are in average range with attention issues reported.
A: In a normal population, the expected mean VIQ-PIQ discrepancy is zero (VIQ is short for Verbal IQ and PIQ is Performance IQ). When there is a large discrepancy between verbal and performance IQ, it generally points out to a learning difficulty or overcompensation and/or impairment of some kind. For instance non-verbal learning difficulty (NVLD) is usually suspected when there is a high VIQ-PIQ difference (VIQ>PIQ).
Usually when a discrepancy of at least 12 points is found between the VIQ & PIQ, the Full Scale IQ score should be interpreted cautiously. Even though the verbal-performance discrepancy is not used to directly diagnose a learning disability, it is like a red flag – it alert parents and teachers to the child's strengths and weaknesses. Therefore, a full analysis of the individual subtests that comprise each score should be looked at and if scatter is very large, it warrants further investigation.
Research has indicated that a discrepancy towards verbal (VIQ > PIQ) has also been linked with Asperger's syndrome but not with other pervasive developmental disorders. Relatively low VIQ has been considered an indicator of dyslexia and relatively low PIQ of dyspraxia. Studies have also suggested that hyperactivity in children is associated with relatively low performance IQ. In more recent studies, it is found that there is a high degree of individual and familial comorbidity between these three disorders.
The term clinically significant means that the severity of the behaviour/performance is significantly different from the norm and indicates a strong possibility of a clinical problem.
Hope that helps. Good luck!
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