ICD-10-CM > R00-R99 > R90-R94 > R94 > R94.0 R94.0 Abnormal results of function studies of central nervous system Non-Billable/Non-Specific Codes R94.01Abnormal electroencephalogram [EEG]R94.02Abnormal brain scanR94.09Abnormal results of other function studies of central nervous system