A case of claimed complete blindness: Forced-choice testing in forensic neuropsychological examinations

Tailor-made forced-choice validity testing was introduced in the 1970s and 1980s as a method to investigate cases of suspected malingering, but with the widespread use of standardized performance validity tests it seems to have lost much of its attraction. This is the case report of claimed complete visual loss in a constellation where ophthalmologists had excluded an underlying ocular disease for years, with the exception of scars after unilateral retinal detachment. The 50-year-old claimant had undergone a court-ordered psychiatric evaluation that confirmed the presence of a dissociative blindness and recommended to legally treat the claimant like a case of genuine blindness. The judge of a state court-of-appeal finally ordered a neuropsychological evaluation to clarify the true nature of the claimed blindness. Four different tailor-made forced-choice tests were constructed. On all of them, the claimant scored significantly below chance and demonstrated that, in fact, he was able to recognize the visual stimuli used on the tests. Taylor-made forced-choice procedures attract little attention in the current neuropsychological literature, but they offer a powerful approach to differential diagnosis in specific symptom constellations for which standardized testing is not available. Unclear symptom constellations like in this case can be resolved by tailor-made testing.