Visual and auditory event related potentials in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is classically described as an upper and lower motor neuron disease without clinical sensory disorders. Various studies have been conducted to explore and understand motor impairment but in the last years also cognitive functions have drawn attention in ALS patients investigating extra-motor involvment. Recent neuropsychological studies have been carried out to evaluate specific cognitive dysfunction also supported by MRI, PET and SPECI findings. All papers report subtle cognitive impairment especially related to the frontal lobe functions. Gil et al (1995) performed an auditory ERPs study and they found 60% of patients had P300 delayed latency. To further investigate the relationship between ALS and cognitive function, visual and auditory oddball ERPs were recorded in 10 patients by using 30 electrodes. Attention was focused on latency and amplitude of P300 and on its topographic distribution. Neuropsychological evaluation allowed to test the cognitive status of patients and psychometric tests were selected to assess intelligence, executive functions, attention, memory, word fluency, visuo-motor and visual-constructive skills. Motor disability was scored by ALS Severity Scale including bulbar and spinal score. Depression state was evaluated by using Hamilton Scale. Results of ERPs were compared to 10 healthy age-matched controls. Preliminary data show abnormalities of P300 in about 50% of patients. Correlations between visual and auditory P300 latency and amplitude, psychometric tests, disease duration, physical disability and depression will be discussed