Primary and Secondary Progressive Aphasia in Posterior Cortical Atrophy.

Background: Posterior cortical atrophy (PCA) is a clinico-radiological syndrome characterized by a progressive decline in visuospatial/visuoperceptual processing. PCA is accompanied by the impairment of other cognitive functions, including language abilities.

Methods: The present study focused on three patients presenting with language complaints and a clinical profile that was compatible with PCA.

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.

Comparison of two models of hemispheric specialization with unilaterally lesioned patients: material-specific impairment vs response-bias distortion.

Validity of two models of hemispheric specialization was compared. The "material-specific impairment" model was radicalized as postulating that left hemisphere (LH) lesions impair processing of verbal material and that right hemisphere (RH) lesions impair processing of visuospatial material, independently of response-bias distortions. The "response-bias distortion" model was radicalized as postulating that LH lesions distort response style toward omissiveness and that RH lesions distort response style toward commissiveness, regardless of material-specific impairments.

Specific early vulnerability of high-order executive function to focal brain lesions and long-term impact on educational persistence: Sparing of incidental episodic memory.

Objective: We investigated mental functions expected to remain impaired or not ain adulthood following childhood-onset brain lesions.

Methods: Thirty unilaterally lesioned young adults were tested a decade after lesion onset with an effort-demanding complex executive function (EF) task as well as a task of incidental declarative retrospective episodic recognition memory (IRM). Thirty neurotypical participants were also tested.

Ictal hallucination and hemispheric specialization: findings from 217 cases with a unilateral epileptic focus.

Epileptic populations are generally considered inappropriate to investigate hemispheric specialization. However, (1) because hallucination occurs in the early stage of the ictus during which activation is observed in and around the focus, the former could be a direct result of the latter (hypothesis 1), and (2) the type of psychological content of ictal hallucination could depend on which hemisphere is ictally activated (hypothesis 2). It was predicted that, on the basis of quantitative analysis of previously published singles case reports, unilateral ictal hallucinations should occur in the visual field, ear or hemibody contralateral to the side of the ictal focus (test of hypothesis 1).

Visual hypo and hypergnosia as exemplars of poles of psychic tonus in the occipital lobes: multiple case analyses.

The "psychic tonus" model or PTM [1] of hemispheric specialization states that the left hemisphere is a psychic and behavioral activator and that the right hemisphere is an inhibitor. The PTM predicts that the tonus of visual representation ought to manifest hemispheric specialization in the occipital lobes. Specifically PTM predicts that pathological positive visual tonus (visual hallucination) ought to be associated more frequently with right occipital lesions.

Post unilateral lesion response biases modulate memory: crossed double dissociation of hemispheric specialisations.

We propose that what appears to be hemispheric specialisation in the memory domain, as indexed by effects of unilateral brain lesions, is to a great extent explainable as response bias: left hemisphere lesions result in an omissive response bias or error pattern whereas right hemisphere lesions result in a commissive response bias or error pattern. To test this prediction a group of 40 non-confabulatory cases with a verbal and non-verbal retention deficit (hypomnesia), subsequent to a unilateral lesion, was assembled from the literature. A group of non-amnesic cases with confabulation, paramnesia, false memories or memory-laden hallucination (dysfunctional hypermnesia), due to a unilateral lesion, was also assembled from the literature (N=72).

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.

Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition symptoms of mania: which one(s) result(s) more often from right than left hemisphere lesions?

Previously published single case reports of patients with a unilateral lesion were assembled. After the lesion, each of the 244 cases presented at least one of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) symptoms of a manic episode, namely, elated or irritable mood, grandiosity, talkativeness, flight of ideas, hyperhedonism, reduced need for sleep, agitation, or distractibility (all optional in DSM-IV). As expected, the subgroup of 59 manic patients had a right hemisphere lesion far more often than a left one.

An orbitofrontostriatopallidal pathway for morality: evidence from postlesion antisocial and obsessive-compulsive disorder.

Introduction: A detailed proposal is made to the effect that nonlesional antisocial personality disorder (APD) is, among other things, a dysfunctional hypomoralism and that nonlesional obsessive-compulsive disorder (OCD) is, among other things, a dysfunctional hypermoralism.

Method: To provide an empirical test of this proposal, 25 previously published cases of acquired (post lesion) APD and 39 cases of acquired OCD are reviewed and compared with multivariate inference tests.

Results: The acquired APD patients most often present putamenal or pallidal lesions.

Ictal fear depends on the cerebral laterality of the epileptic activity.

Glascher and Adolph (2003) proposed that both amydalae are specialized for fear, but that the right one is a fast, short, and relatively automatic fear processor, whereas the left one is more detail-oriented and perceptual-cognitive. According to this model, early ictal fear should occur more often in cases with a right temporal lobe epileptic focus. Several authors have tried to find a hemispheric specialization for ictal fear, but have not reached the power to attain a statistically significant effect of focus side.

Auditory hypergnosia as an example of psychic tonus in the temporal lobes: multiple case analyses.

In 2006, Braun proposed a new model of hemispheric specialization of energy management by the brain, which he termed the "psychic tonus" model of hemispheric specialization. The term "psychic tonus" is deliberately general. It invites further investigation designed to incorporate various behavioral and cognitive modalities.

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).