Neurological and Neuropsychological

Concern has frequently been expressed about the potential dangers of solvent abuse. Reports of youngsters dying shortly after sniffing solvents have been widely publicized and worries about the possibility that those who do not die will suffer physical harm have often been voiced. 

The risk of sudden death has been well documented both in the USA (Bass, 1970) and the UK (Watson, 1979 Anderson et al, 1985). Approximately half of the recognised fatalities appear to be caused by a direct toxic effect of the solvent, probably on the heart. The other half are attributable to more indirect causes such as aspiration of vomit, plastic bag suffocation, and accidents sustained while intoxicated (Anderson et al, 1985). 

In the UK the number of fatalities attributed to solvent abuse rose sharply between 1975 and 1985 (Anderson et al, 1985) such that the practice is now a significant factor in teenage mortality. Nevertheless, in absolute terms, fatalities are still quite rare. Until 1984, for example, the total number of such deaths throughout the UK was less than a hundred per year. If this figure is contrasted with the proportion of young people who have tried abusing solvents, a figure of 4 to 5% in two of the more satisfactory British studies (NOP, 1982 Plant, Peck and Samuel, 1985), it is clear that the vast majority of those who sniff do not die as a result of the practice. 

Before considering the literature on solvent abuse, it is convenient to mention briefly the evidence from studies of people exposed to solvents in the course of their work. A number of investigations, particularly from Sweden and Finland, 

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Boiler F, Duyckaerts C. (1997). Alzheimer s disease Clinical and anatomic aspects. In Behavioral Neurology and Neuropsychology. Feinberg T, Farah MJ, eds. New York McGraw-Hill. 

The sequelae of acute poisoning appear to be quite variable and depend on duration of exposure as well as level of exposure. Patients who have been unconscious in high levels of hydrogen sulfide atmosphere for longer than 5 min may have persistent neurological and neuropsychological impairment years after exposure as a result of hydrogen sulfide-induced hypoxia. ... 

Krakowski M. 1997. Neurologic and neuropsychologic correlates of violence. Psychiatr Ann 27 674-678. 

Of 24 solvent abusers (mean age 23 years), who had used substances containing a mean of 425 mg of toluene per day for an average of 6.3 years, 16 had marked impairment in neurological and neuropsychological tests cerebellar symptoms were particularly prominent (21). The impairment correlated significantly with CT scan measurements of the cerebellum, ventricles, and cortical sulci, all of which were abnormal compared with age-matched controls. 

Long-term neurological and neuropsychological effects that sometimes follow recovery from acute toxicity, and which may persist for years. 

Neurologic and neuropsychologic symptoms reported included difficulty concentrating, memory loss, numbness in the face or extremities, shaking, tremors, headache, and sleep disorders. Industrial hygiene evaluation... 

For a diagnosis, clinicians rely on histories, on physical, neurological and psychiatric examinations, on neuropsychological tests [1,14], and on laboratory studies [15,16]. 

Polybrominated Biphenyls. Examination of children ( 100 were identified) presumably exposed in utero or in early infancy during the peak of the Michigan PBB contamination episode and whose families lived on farms known to be contaminated with PBBs has not revealed any consistent or maiked abnormalities in the children s physical and neuropsychological development. No significant abnormalities were found by physical and neurological examination of 33 of these exposed children when they had a mean age of... 

Darby DG, Donnan GA, SaUng MA et al. (1988). Primary intraventricular haemorrhage clinical and neuropsychological findings in a prospective stroke series. Neurology 38 68-75. Derex L, Nighoghossian N, Hermier M et al. (2004). Thrombolysis for ischemic stroke in patients with old microbleeds on pretreatment MRI. Cerebrovascular Diseases 17 238-241... 

Morris JC, Heyman A, Mohs RC, Hughes JP, van BeUe G, FiUenbaum G, MeUits ED, Clark C (1989) The Consortium to Establish a Registry for Alzheimer s Disease (CERAD). Part I. Clinical and neuropsychological assessment of Alzheimer s disease. Neurology 39 1159-1165... 

Parkinson, R.B., Hopkins, R.O., Cleavinger, H.B., Weaver, L.K., Victoroff, J., Foley, J.F., Bigler, E.D. (2002). White matter hyperintensities and neuropsychological outcome following carbon monoxide poisoning. Neurology 58 1525-32. 

The neurophysiological and neuropsychological health effects of mercury have been extensively studied in occupationally exposed individuals in an effort to monitor body levels and to determine a threshold value below which these effects are unlikely to occur. As with other biomarkers of effect, neurological changes induced by mercury may resemble exposure to other chemicals that can cause damage to the brain. 

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