The effectiveness of these medications appears to be modest but significant for a large number of patients who can tolerate their side effects. On average, the cognitive enhancers slow down for six months or more the encroachment of Alzheimer's disease on multiple areas of functioning. "This study is important because it demonstrates that although milder therapeutic drugs (such as riluzole) have been shown in animal models and are currently being tested by doctors treating several different types Parkinsonian disorders, they don't eliminate both neurodegenerative symptoms and impairments in normal memory," says Dr Wollenbergs. He adds: I believe this paper will help us further understand how the medication works with cognition impairment. So the drug is effective for a fixed time or months.