Criteria for solvent-induced chronic toxic encephalopathy: a systematic review

Abstract

In 1985, a WHO Working Group presented diagnostic criteria and a classification for solvent-induced chronic toxic encephalopathy (CTE). In the same year, the "Workshop on neurobehavioral effects of solvents" in Raleigh, N.C., USA introduced a somewhat different classification for CTE. The objective of this review is to study the diagnostic procedures that are used to establish the diagnosis of CTE, and the extent to which the diagnostic criteria and classification of the WHO, and the classification of the Raleigh Working Group, are applied. A systematic search of studies on CTE was performed, and the diagnostic criteria and use of the WHO and Raleigh classifications were listed. We retrieved 30 original articles published in English from 1985 to 1998, in which CTE was diagnosed. Only two articles did not report the duration of solvent exposure. The type of solvent(s) involved was described in detail in four articles, poorly in 17 articles, and not at all in nine articles. Tests of general intelligence were used in 19 articles, and tests of both attention and mental flexibility and of learning and memory were used in 18 articles. Exclusion, by interview, of potentially confounding conditions, such as somatic diseases with central nervous effects and psychiatric diseases, was reported in 21 and 16 articles, respectively. In only six of the articles were both the WHO diagnostic criteria and the WHO or Raleigh classifications used. In the future, parameters of exposure, psychological test results, and use of medication that possibly affects psychological test results should always be described. We list some advantages and disadvantages of the Raleigh and WHO classifications. To aid inter-study comparisons, the diagnosis of CTE should be categorized and reported according to an internationally accepted classification.

Symptom screening in detection of occupational solvent-related encephalopathy

“…The follow-up from 2002 to 2006 revealed clinical data which enabled the diagnostic judgement. Two cases out of four had encephalopathy with neuropsychological findings progressing after cessation of exposure, which is not accepted by the diagnostic criteria (Edling et al 1990;van der Hoek et al 2000). Thus, occupational solvent exposure was not considered to be in a main causative role in these encephalopathies.…”

“…Thus, there are prerequisites for diagnostics: evidence of necessary exposure, no latency between symptoms/signs and exposure, exclusion of other etiologies which may affect cognition and typical findings of cognitive dysfunction shown by neuropsychological testing (Juntunen 1993;van der Hoek et al 2000;Triebig and Hallermann 2001).…”

Persistent cognitive functioning deficits in operating rooms: two cases

“…In these two cases, progressively appearing symptoms such as mood disturbances and cognitive deWcits are consistent with CTE stage 2B ( Van der Hoek et al 2000). Interview, examination, investigations and non-evolution of symptoms after cessation of exposure exclude primary neurological (cerebrovascular or neurodegenerative diseases), endocrinal, metabolic, infectious or alcoholic etiology.…”

“…Early symptoms such as fatigue, memory impairment, loss of initiative and diYculty in concentration develop insidiously and gradually over many weeks. If exposure persists, marked and sustained changes in personality or mood appear and later possibly irreversible cognitive functions impairment occurs (Van der Hoek et al 2000).…”

Psychological Treatment of Patients with Chronic Toxic Encephalopathy: Lessons from Studies of Chronic Fatigue and Whiplash

“…Thus, CTE is diagnosed by the exclusion of other causes, based on consensus by a multidisciplinary diagnostic team. Two international working groups have proposed slightly different diagnostic criteria for CTE [4, 5], but neither set of criteria appears to be widely used in clinical practice [6, 7]. Neuropsychological assessment is the cornerstone for identifying the subtle and otherwise difficult to detect neurobehavioral consequences of exposure, but has methodological weaknesses, such as the lack of control over variables (for example, suboptimal performance or malingering and social expectancy effects).…”