Why does a liver disorder make you slower than a normal person?

Encephalopathy : In severe liver disease, a condition known as hepatic encephalopathy can occur. Essentially, it results from the liver's inability to process toxins such as ammonia from the body. It could range from mild impairment to deep coma and everywhere in between. There are some medicines which help, but nothing which completely cures this other than treating the baseline liver disease. Hope this helps.