| Type 1 |
Symptoms only |
Symptoms include impaired memory, poor concentration, fatigue, and reduced motivation. Where exposure ceases these non‐specific symptoms will resolve. |
| Type 2A |
Sustained personality or mood change |
Altered personality with lowered mood, reduced motivation, poor impulse control, anxiety, and irritability. |
| Type 2B |
Impairment in intellectual function |
Neuropsychological testing shows cognitive deficits affecting attention/concentration, visuospatial skills, and verbal memory. There may be minor neurological signs. If exposure ceases some recovery is likely but full recovery may not occur. |
| Type 3 |
Dementia |
Cognitive impairment is often accompanied by neurological deficits. Nerve conduction studies, electromyography, or neuroradiology (CT or MRI scanning) may identify abnormalities. Deficits do not usually worsen if withdrawn from further exposure. |
