Dissociation between verbal response initiation and suppression after prefrontal lesions.

Some of the most striking symptoms after prefrontal damage are reduction of behavioral initiation and inability to suppress automatic behaviors. However, the relation between these 2 symptoms and the location of the lesions that cause them are not well understood. This study investigates the cerebral correlates of initiation and suppression abilities assessed by the Hayling Sentence Completion Test, using the human lesion approach. Forty-five patients with focal brain lesions and 110 healthy matched controls were examined. We combined a classical group approach with 2 voxel-based lesion methods. The results show several critical prefrontal regions to Hayling Test performance, associated with either common or differential impairment in "initiation" and "suppression" conditions. A crucial role for medial rostral prefrontal cortex (BA 10) in the initiation condition was shown by both group and lesion-mapping methods. A posterior inferolateral lesion provoked both initiation and suppression slowness, although to different degrees. An orbitoventral region was associated with errors in the suppression condition. These findings are important for clinical practice since they indicate that the brain regions required to perform a widely used and sensitive neuropsychological test but also shed light on the regions crucial for distinct components of adaptative behaviors, in particular, rostral prefrontal cortex.

The selective impairment of arithmetical procedures.

The theoretical distinction between arithmetic facts and procedures was first made by Groen and Parkman (1972). This was confirmed with a neuropsychological single case described by Warrington (1982) who had impaired arithmetical facts but well preserved arithmetical procedures. Since this time there have been several patients described who showed a selective impairment of arithmetic facts. There have also been reports of cases with impaired arithmetical procedures. However, there has not yet been a case reported with the selective impairment of procedures in the context of intact arithmetic facts. This paper describes a patient, SR, with probable Alzheimer's dementia who had well preserved addition, multiplication and subtraction facts but who nevertheless had severe difficulties with a range of arithmetical procedures such as multidigit sums, decimals and fractions. The implications of this case for current theoretical models are discussed.

Rehabilitation outcomes after brain injury: disability measures or goal achievement?

BACKGROUND: The outcome of rehabilitation interventions following brain injury is commonly rated by disability scales. Goal-setting and achievement are important in inpatient rehabilitation, but seldom assessed as outcomes. OBJECTIVE: To compare the information acquired from using disability ratings and goal attainment/variances as outcome measures in brain injury rehabilitation. SETTING: An inpatient regional neurological rehabilitation unit. SUBJECTS: One hundred and seventy-seven patients admitted after single incident brain injury over a three-year period. MAIN MEASURES: (1) Disability outcomes by the Barthel Index and the Functional Independence Measure, (2) goal achievement and variance distribution, and (3) the influence of diagnosis and demographics on these measures. RESULTS: Patients improved significantly on all disability scales employed (p < 0.0001), with the baseline admission scores being inversely correlated with changes in dependency by discharge (rho approximately -0.4). The median attainment rate of long-term goals was 75% per patient. Nonachievement was most frequently due to cognitive problems (38%), followed by behavioural difficulties and physical limitations (18% each). Goal achievement correlated poorly with disability outcome at discharge (rho < 0.3). Patients who accomplished all their goals tended to be less disabled at admission. Diagnostic groups and demographic factors had little influence on either disability or goal achievement outcomes. CONCLUSIONS: The use of a simple goal achievement and variance coding scheme has been relatively straightforward to incorporate into the daily practice of the unit. It provides useful information on rehabilitation process and outcome after brain injury that is complementary to the utilization of disability measures.