A careful neuropsychological examination shows that intellectual impairments in such patients reveal the same features which are exhibited in a more conspicuous form by patients with a marked frontal syndrome. This chapter discusses various typical cases which allows to describe in detail the structure of intellectual impairments of an indistinct frontal syndrome. Patient U, 39-years-old, an engineer, was admitted to the Institute of Neurosurgery in March 1964, complaining of headaches which began in 1963. During the summer of 1963, she had an attack unaccompanied by cramps which resulted in loss of consciousness. Patient D, 51-years-old, an administrative officer, was admitted to the Institute of Neurosurgery complaining of severe headaches. Facts convincingly prove that a measurable intellectual disorder is one of the most subtle symptoms of an injury to the frontal lobes, which can be observed even in the cases when all other methods for the assessment of higher cortical functions fail to demonstrate any impairment.