Chronic solvent-induced encephalopathy: course and prognostic factors of neuropsychological functioning.

PURPOSE: Working in conditions with daily exposure to organic solvents for many years can result in a disease known as chronic solvent-induced encephalopathy (CSE). The aims for this study were to describe the neuropsychological course of CSE after first diagnosis and to detect prognostic factors for neuropsychological impairment after diagnosis. METHODS: This prospective study follows a Dutch cohort of CSE patients who were first diagnosed between 2001 and 2011 and underwent a second neuropsychological assessment 1.5-2 years later. Cognitive subdomains were assessed and an overall cognitive impairment score was calculated. Paired t tests and multivariate linear regression analyses were performed to describe the neuropsychological course and to obtain prognostic factors for the neuropsychological functioning at follow-up. RESULTS: There was a significant improvement on neuropsychological subdomains at follow-up, with effect sizes between small and medium (Cohen's d 0.27-0.54) and a significant overall improvement of neuropsychological impairment with a medium effect size (Cohen's d 0.56). Prognostic variables for more neuropsychological impairment at follow-up were a higher level of neuropsychological impairment at diagnosis and having a comorbid diagnosis of a psychiatric disorder at diagnosis. CONCLUSIONS: Results are in line with previous research on the course of CSE, stating that CSE is a non-progressive disease after cessation of exposure. However, during follow-up the percentage patients with permanent work disability pension increased from 14 to 37%. Preventive action is needed in countries where exposure to organic solvents is still high to prevent new cases of CSE.

Validity of the Groningen Effort Test in patients with suspected chronic solvent-induced encephalopathy.

INTRODUCTION: The use of performance validity tests (PVTs) in a neuropsychological assessment to determine indications of invalid performance has been a common practice for over a decade. Most PVTs are memory-based; therefore, the Groningen Effort Test (GET), a non-memory-based PVT, has been developed. OBJECTIVES: This study aimed to validate the GET in patients with suspected chronic solvent-induced encephalopathy (CSE) using the criterion standard of 2PVTs. A second goal was to determine diagnostic accuracy for GET. METHOD: Sixty patients with suspected CSE referred for NPA were included. The GET was compared to the criterion standard of 2PVTs based on the Test of Memory Malingering and the Amsterdam Short Term Memory Test. RESULTS: The frequency of invalid performance using the GET was significantly higher compared to the criterion of 2PVTs (51.7% vs. 20.0% respectively; p < 0.001). For the GET index, the sensitivity was 75% and the specificity was 54%, with a Youden's Index of 27. CONCLUSION: The GET showed significantly more invalid performance compared to the 2PVTs criterion suggesting a high number of false positives. The general accepted minimum norm of specificity for PVTs of >90% was not met. Therefore, the GET is of limited use in clinical practice with suspected CSE patients.

Pitfalls in clinical assessment of neurotoxic diseases: negative effects of repeated diagnostic evaluation, illustrated by a clinical case.

Exposure to different toxic substances can have acute and chronic neurological and neuropsychiatric health effects on humans. Patients often report impaired concentration and memory, irritability, fatigue, instability of affect and difficulties in impulse control. The diagnostic process for neurotoxic diseases is complex and relies heavily on the exclusion of differential diagnosis and substantiating the cognitive complaints by neuropsychological assessment. Diagnostic evaluations have the purpose to help the patient by finding an explanation for the symptoms to guide treatment strategy or prevent further deterioration. But what if the diagnostic process in itself leads to problems that can be quite persistent and difficult to manage? The iatrogenic, or sick-making, side effects of the diagnostic process are the main focus of this case study.