An attempt has been made to study the ability of patients with amyotrophic lateral sclerosis (ALS) to 'plan' a task. Electroencephalogram (EEG) data corresponding to 'planning of a movement task' is analyzed in comparison with a normal relaxed state. The study was conducted on 12 patients with ALS (6 males, 3 females, mean age 46.75 years) and on same number of controls (10 males, 2 females, mean age 48.75 years) to evaluate a difference in the ability to 'plan' a movement task between them. Patients with ALS were divided in two groups defined by unclear/clear speech. It has been observed that patients with ALS having unclear speech (Group I) showed considerable reduction (p<0.0001) in 'planning' a movement task, whereas patients with ALS having clear speech (Group II) showed no deficit in 'planning' a movement task (p=0.0577), both in comparison with age-matched controls. Apart from supporting the earlier reports of a possible extended neuronal degeneration across wide area of the frontal lobes, the findings reveal a possible reduction in planning, an executive function of the prefrontal cortex of brain, and also reveal that speech impairment may be associated with cognitive deficits in patients with ALS.