Lucie Godbout

Cognitive structure of executive deficits in frontally lesioned head trauma patients performing activities of daily living.

OBJECTIVE Executive functions in activities of daily living (ADL) were investigated in 10 patients with frontal lobe lesions after a mild to severe closed head injury (CHI). METHOD The CHI patients were compared to 12 normal controls with a neuropsychological test battery, a script recitation task and a realistic simulation of complex multitask ADL (planning and preparing a meal). RESULTS Though the CHI patients were significantly slow on one test and subject to interference on an attention test with parametric testing, the groups did not differ on any neuropsychological test with non parametric testing. However, the CHI patients manifested marked anomalies in the meal preparation task. While small sequences of actions were easily produced, large action sets could not be correctly executed. CONCLUSION An outstanding deficit in strategic planning and prospective memory appears to be an important underpinning of the impairment of ADL observed in CHI patients with frontal lobe lesions.

Opposed Left and Right Brain Hemisphere Contributions to Sexual Drive: A Multiple Lesion Case Analysis

Brain topographical studies of normal men have have shown that sexual excitation is asymmetric in the brain hemispheres. Group studies of patients with unilateral epileptic foci and other studies of patients with unilateral brain lesions have come to the same conclusion. The present study reviewed previously published single case reports of patients with frank hypo or hypersexuality subsequent to a unilateral brain lesion. Hyposexual patients tended to have left hemisphere lesions (primarily of the temporal lobe), and hypersexual patients tended to have right hemisphere lesions (primarily of the temporal lobe) (p < 0.05). We interpret this double dissociation as part of a more general phenomenon of psychic tone similarly dissociated with regard to hemispheric control, including mood, psychomotor baseline, speech rate, and even immunity. The behavioral significance of this psychic tone is to modulate approach versus avoidance behavior.

Executive Functions and the Obsessive-Compulsive Disorder: On the Importance of Subclinical Symptoms and Other Concomitant Factors

Although reviews concerning the neuropsychology of obsessive-compulsive disorder (OCD) put great emphasis on impaired executive functioning, the overall conclusions are notoriously divergent. The main goal of the present study was to use a battery of neuropsychological tasks to assess nine cognitive domains with a special focus on executive functions in 40 patients with OCD. A secondary objective was to examine the relationships between clinical or demographic variables and neuropsychological performances. The third goal was to separate executive functions in more homogeneous components to verify whether specific impairment might be found in persons with OCD. Confirming the main hypothesis, few neuropsychological differences emerged between the OCD and healthy participants when concomitant factors were controlled. Moreover, subclinical symptoms appeared to play a different and independent role on the cognitive results. Future studies should include more specific tasks of lower-order executive functions among persons with OCD to confirm this possibility.

Defective Representation of Knowledge in Parkinson's Disease: Evidence from a Script-Production Task☆

The deficits seen in frontal-lobe patients and in the elderly show clearly that spontaneous script generation depends on good frontal-lobe function. Shallice, however, has proposed that one aspect of script generation (contention scheduling, CS) which is involved in the activation and maintenance of overlearned or routine scripts may depend more on the basal ganglia. Patients with Parkinsons disease would thus be expected to manifest deficits somewhat different from those observed in frontal-lobe patients when generating scripts. The performances of 16 nondemented and nondepressed patients with idiopathic Parkinsons disease were compared to those of 16 age-matched normal control subjects under two experimental conditions; routine, forward script generation and nonroutine, backward script generation. Parkinsonian patients generated scripts significantly deprived of contextual elements in the forward condition and made significantly more sequencing and perseverative errors in both forward and backward conditions than did normal subjects. They also produced a significantly higher number of irrelevant intrusions, in both conditions, than did controls. These results support, in a general sense, Shallices notion that the basal ganglia are important in script generation; however, other specific predictions of Shallices model were not supported by our findings.

Remembering the Past and Foreseeing the Future while Dealing with the Present: A Comparison of Young Adult and Elderly Cohorts on a Multitask Simulation of Occupational Activities

Thirty-five young adult and 38 elderly cybernauts, matched for education, sex, alcohol consumption, and time/day of computer use were compared on a computerized simulation of professional activities of daily living (ADLs). The program quantified performance in terms of speed and accuracy on four major constructs: (1) planning (a 30-item office party script); (2) prospective memory (injections, sleep, phone); (3) working memory (PASAT, D2, and CES analogs); and (4) retrospective memory. Participants had to organize an office party, self inject insulin and go to bed at requisite times of day, do “office work” at unpredictable times of day, and answer the phone that blinked but did not ring (near threshold stimulus). The elderly were markedly and equally impaired on all four constructs (F = 24.3, p < .000). The elderly were also equally and markedly impaired on slave and central executive systems (c.f. Baddeleys model) and on event-based and time-based prospective memory (c.f. McDaniels model)—findings arguing against a “frontal” model of cognitive decline. This supports Salthouses concept of a “general factors” decline in normal aging due to diffuse deterioration of the brain. On the other hand, as expected from previous findings, the balance of omissiveness/commissiveness was significantly increased in the elderly samples error profile. Furthermore, the balance of speed and accuracy was significantly increased in the elderly. This defines limits of the “general factors” model. The elderly also markedly underused a clock icon which had to be clicked on to get the virtual time of day necessary for integrating all the required actions. Prospective memory explained 11% of the aging variance despite partialing out of the three other constructs, making it appear as a golden standard of sensititivity to normal aging—though perhaps provided it be implemented in a distracting, multitask, strategically demanding context.

A Verbal Planning Impairment in Adult ADHD Indexed by Script Generation Tasks

Objective: Though juvenile and adult ADHD cases are well known to have a nonverbal planning impairment, a verbal-planning impairment has been demonstrated only in juvenile ADHD. The purpose of this investigation is to determine whether a verbal planning impairment also characterizes adult ADHD. Methods: A cohort of 30 adult ADHD clients of a university psychological clinic are compared to 30 age-, education-, gender-, and IQ-matched persons recruited from the general population who did not have ADHD. The dependent measure is a set of 6 paper/pencil 10-item script generation tasks. Results: The findings reveal that the ADHD cohort was significantly impaired on the script task and the script task correlated significantly with severity of ADHD (CAARS index + WURS), whereas several neuropsychological measures of executive function (Stroop, COWA, Rey’s Complex Figure, D2, CVLT, CPT-II) did not. Findings further showed that the script measure was weakly correlated with the other established neuropsychological measures of executive function (r < .46, shared variance of less than 21%). Conclusions: On the basis of the study findings, it is concluded that verbal planning measured with script generation tasks is distinctly impaired in clinically referred adult ADHD.

The Relative Importance of Suboperations of Prospective Memory

An event-based and a time-based prospective memory (PM) task, a script generation task, several working memory tasks, an incidental retrospective memory task, and a screen clock were implemented on the computer in one integrated procedure lasting between one and two hours. The procedure was designed to simulate four working days and four nights for a white-collar employee. Sixty-eight normal participants completed the task. Time-based prospective memory (self-injecting and going to bed at preordained times of day) shared unique variance with clock checking, but hardly at all with incidental retrospective memory. On the other hand, event-based prospective memory (answering a faint telephone cue as quickly as possible) shared unique variance with incidental retrospective memory of formally task irrelevant context and less with clock checking. The latter correlational dissociation of event-based versus time-based PM by retrospective memory reached significance, inspiring the idea that administrative versus clerical work might each impose its own type of PM demands. In both types of PM, low-level abilities (use of external aids and incidental encoding of context, respectively) seem to be critical for good performance, more so than for high-order executive functions. Our software is offered to the readership to explicitate these findings further or for other research pursuits.

Mental Genesis of Scripts in Adolescents With Attention Deficit/Hyperactivity Disorder

Twenty nine ADHD adolescents and 29 age, IQ and gender matched normal comparison subjects completed 6 paper pencil tasks of mental script generation. Each task required the subject to generate 10 chronologically ordered and necessary actions toward a goal. There were 3 levels of structure of the tasks (highly structured, moderately structured, unstructured) and each of these levels comprised a familiar and an unfamiliar script. The ADHD group made more sequencing errors on all the scripts, significantly so on the highly structured unfamiliar and on the moderately structured unfamiliar script tasks. The two groups were similar however with regard to the semantic structure (content) of the scripts and the total number of actions generated. Errors of omission, commission and perseveration were similar for the two groups. The results are interpreted as supportive of Barkleys (1997) frontal lobe dysfunction model of ADHD.