Disorders of frontal lobe functioning.

The neurology of frontal lobe disorders can be summarized in descriptions of behavioral problems (apathy, etc.), of cognitive impairments (poor planning, etc.), and of motor deficits (grasp reflex, etc.). Reviews of this sort do not indicate, however, any regional specificity to the deficit profiles or identify any of the component processes of the complex deficits-what exactly is "poor planning"? In this review we present specific steps that assist in overcoming the limitations: (1) identify weaknesses in current understanding, (2) operationally define the processes to be analyzed, (3) review some methodologies that allow parsing of discreet processes into specific frontal regions, (4) review the unique advantages and disadvantages of the various neurological disorders that provide us with subjects for study, and (5) propose approaches to advance further a useful clinical neurology of frontal lobe disorders as well as a more finely grained scientific description of core frontal processes.