Specific numerical processing impairment in ALS patients

The present study investigated for the first time numerical processing in sporadic amyotrophic lateral sclerosis (ALS) patients. Twenty-four non-demented patients affected by probable or definite ALS and 27 healthy controls underwent cognitive assessment. Numerical abilities (Number Comprehension, Number Transcoding, Arithmetic Fact retrieval, Calculation Skills and Arithmetic Principles) and neuropsychological functions were evaluated in accordance with Strong's consensus criteria. Clear group differences between the patients and controls were found in Multiplication Facts (Tables), Multiplication Approximation, and Multiplication Principles. These deficits were not statistically related to impairments of more general cognitive functioning. In conclusion, specific, previously unreported arithmetical deficits have been found in ALS patients. This particular impairment pattern could be indicative of damage to the cortico-subcortical circuits involved in some specific aspects of multiplication. Our findings could contribute to further delineate the profile of cognitive impairment in ALS.