Earlier is better: the benefits of early diagnosis

The concept of earlier diagnosis of amyotrophic lateral sclerosis (ALS) req uires in-depth investigation of its benefits and consequences. First, how g ood must a treatment be before ALS is determined to be a treatable conditio n? Analogy with cancer therapy suggests that a good quality of life after t reatment is an essential feature of a "good" therapy. Survival in some dise ases may be prolonged without a significant improvement in the patient's qu ality of life. Neurologists need to be clear about what they are trying to achieve in prolonging survival and maintaining a good quality of life for t heir patients with ALS. Second, can early diagnosis extend apparent surviva l in the absence of a therapeutic intervention that significantly affects t he disease process? Earlier diagnosis on the basis of confirmed clinical si gns and, earlier institution of therapy may lead to a perception of improve d survival, which is greater in young ALS patients. Third, can early diagno sis provide a benefit through prolongation of the time the patient remains able to work? Any therapeutic intervention to slow the early stages of the disease would benefit patients who wanted to maintain their self-esteem by continuing to work. Finally, earlier diagnosis of ALS requires decisions to be made concerning the acceptable rate of misdiagnosis, which at present r eaches 10% false-positive and up to 44% false-negative.