Sylvie Daigneault

Working memory and the Self-Ordered Pointing Task: further evidence of early prefrontal decline in normal aging.

Two major lines of investigation are currently clarifying the nature of the impairment of working memory associated with normal aging. Cognitive psychology has formulated the problem in terms such as the balance of impairment of encoding, retrieval, storage and/or attention, whereas neuropsychology has formulated the problem in terms such as the balance of frontal (executive) versus temporal (mnemonic) degeneration. The findings of this study support the contention that the primary impairment of working memory in early normal aging is an active attentional executive processing deficit. Specifically, on the Self-Ordered Pointing Task, there is significantly ineffective exploitation of top-down clustering strategy as a function of aging. On this task, self-organization of encoding and retrieval must occur simultaneously with ongoing responding. The finding cannot be explained as an impairment of encoding, retrieval, storage, or build-up and/or release of proactive interference, since indexes of these did not discriminate young-adult from middle-aged samples.

Processing of pragmatic and facial affective information by patients with closed-head injuries

Although several affective impairments have been demonstrated to occur following closed-head injury (CHI), deficits of the communicative function of language, particularly sentenial and suprasentential pragmatic aspects, have been suggested, but not demonstrated, to occur. This study compared 31 normals and 31 severely closed-head injured patients matched for age, sex and education. The dependent measures consisted of a facial test of emotion (FTE) and a contextual test of emotion (CTE). The former task consisted of 36 slides representing facial expressions of the six emotions demonstrated by Ekman and colleagues to be transcultural, namely, job, sadness, fear, anger, surprise and disgust. The subject was required to name the appropriate emotion for each slide. The latter task consisted of correctly identifying the appropriate emotion for each of 36 brief verbal narratives representing contexts connotative of the same six transcultural emotions. The CHI patients were impaired overall on the FTE but not the CTE. However, the ability to identify anger was significantly impaired on both tasks when considered in isolation from the other emotions. It was concluded that a processing deficit of primary emotional material, particularly anger, does exist following CHI, but that this deficit is not necessarily independent of task and/or modality parameters. It was also concluded that evidence of a pragmatic deficit of the language function following CHI remains to be provided at this time.

Predictors of Intellectual Function After a Unilateral Cortical Lesion: Study of 635 Patients From Infancy to Adulthood

This study investigated potential predictors of intellectual outcome in 417 children and 218 adults who had sustained a unilateral cortical lesion. Of these, 295 cases were collected from the scientific literature and 340 from medical records at seven hospitals in Canada. Different sets of predictors emerged for the Wechsler Verbal and Performance IQ values, accounting for differing variances (ie, 12.4% and 20.1%, respectively). The volume of the lesion was the factor that explained the most variance (ie, 4.95% and 11.7%, respectively). Age at lesion onset was significantly and positively correlated with verbal intelligence scores. This variable, considered independently or in interaction with other predictors, did not account for a large portion of the variance explained in intelligence. This refutes the commonly held notion that early onset of the insults results in a better prognosis. (J Child Neurol 2004; 19:935-943).

Color discrimination testing reveals early printshop solvent neurotoxicity better than a neuropsychological test battery

Twenty standardized neuropsychological tests were compared to the Lanthony D-15 desaturated panel test of chromotopsia to determine which measures would most effectively discriminate solvent-exposed print workers from controls. All the workers of the printing services of Université du Québec a Montréal (N = 29) were assessed excepted one who refused to participate. Twenty-nine workers (employed on a full time basis) matched for occupation, age, sex, education, vocabulary, and written arithmetic (p >.13) with the print workers served as controls. Air samples revealed exposure to ethanol, perchloroethylene, methyl chloride, xylene, toluene, and stoddard solvent in the print shop. None of the 20 neuropsychological measures yielded a statistically significant decrement in the print workers. On the other hand, the Lanthony D-15 test revealed a significant group difference (p <.01) and a highly significant interaction between job category within the print shop and dyschromatopsia (p <.001) - the graphists, photocopiers, and printers/binders manifesting increasing severity of impairment as a function of increasing magnitude, and/or type, of dose. The results were interpreted to mean that in a cohort of printers with low seniority (10.42 years) such as this one, neuro-opthalmotoxic effects can be observed earlier than putative neuropsychotoxic effects with the tools at hand.

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.

Pseudodepressive personality and mental inertia in a child with a focal, left‐frontal lesion

Very few pediatric cases with focal frontal lesions have been documented psychia‐trically. Orbitofrontal lesions in adults produce a pseudopsychopathic personality syndrome with impulsivity, and dorsolateral and frontomedial lesions produce a pseudodepressive personality syndrome with mental inertia. A frontal profile similar to character disorder several times has been reported in children with frontal lesions, but pseudodepression never has been reported. SC2, a 7‐year‐old girl, had a left‐frontal cavernous hemangioma partially surgically removed at age 3. Low academic achievement and concern about lack of communicativeness and initiative motivated referral. She is a strong prototype of the pseudodepressive‐inert type, but she is not at all a prototype of the pseudopsychopathic‐impulsive type, thus being the first reported pediatric focal frontal lobe lesion case displaying this particular profile. SC2 is a quiet, aloof, amorphous, trouble‐free schoolchild. She is impaired in a wide range of cognitive (...

Evidence from unilateral lesions of early uncompensable implementation of opposed response-biases in each hemisphere of the brain

PURPOSE The intact right hemisphere presents an omissive response-bias and the left hemisphere a commissive response-bias in adults. This research sought to determine whether these hemispherically lateralized response-biases manifest early developmental and uncompensable brain implementation. METHODS Sixteen teenager and adult participants with focal left hemisphere lesions and fourteen with focal right hemisphere lesions (all with childhood onset: M=13 year recovery period) and 14 normal control participants were recruited. A computerized multitask high order working memory procedure was designed to generate many errors of omission and of commission. RESULTS The expected double dissociation of response-bias distortion as a function of lesion side was significantly demonstrated on this task and was significantly frontal-lobe dependent. CONCLUSION The hemispheres of the brain have an opposed response bias that is robustly implemented in infancy through adulthood.