Chronic neurological toxicity associated with exposure to volatile substances.

1. The main neurological disorders associated with chronic VSA are peripheral neuropathy, cerebellar disease, chronic encephalopathy and dementia. Apart from peripheral neuropathy, the clinical features are non-specific, evidence for solvent-related toxicity is in most cases circumstantial and there is no clear dose/response relationship. 2. Peripheral neuropathy is mainly associated with n-hexane and methyl n-butyl ketone. 3. Cerebellar disease is usually associated with toluene exposure; in the more severe cases there is often radiological evidence of irreversible cerebellar atrophy. 4. Chronic encephalopathy and dementia are the most serious consequence of solvent exposure, particularly to toluene in abusers and to mixed solvents in industrial workers. Postmortem studies in some abusers have shown generalized axonal degeneration, demyelination and brain atrophy. 5. Further studies on low level solvent exposure are needed as little is known about the neurological consequences of mild VSA, especially as regards individual susceptibility and possible interactions between solvents and other toxins such as ethanol.