Kyle Brauer Boone

A System for Relational Reasoning in Human Prefrontal Cortex

The integration of multiple relations between mental representations is critical for higher level cognition. For both deductive- and inductive-reasoning tasks, patients with prefrontal damage exhibited a selective and catastrophic deficit in the integration of relations, whereas patients with anterior temporal lobe damage, matched for overall IQ but with intact prefrontal cortex, exhibited normal relational integration. In contrast, prefrontal patients performed more accurately than temporal patients on tests of both episodic memory and semantic knowledge. These double dissociations suggest that integration of relations is a specific source of cognitive complexity for which intact prefrontal cortex is essential. The integration of relations may be the fundamental common factor linking the diverse abilities that depend on prefrontal function, such as planning, problem solving, and fluid intelligence.

Frontal lobe degeneration Clinical, neuropsychological, and SPECT characteristics

The clinical, neuropsychological, and cerebral blood flow characteristics of eight patients with frontal lobe degeneration (FLD) were studied. Social withdrawal and behavioral disinhibition were the earliest and most common clinical presentations, and psychiatric symptoms typically preceded the onset of dementia by several years. Neuropsychological testing showed selective impairment of frontal and memory tasks with relative sparing of attention, language, and visuospatial skills. Single-photon emission computerized tomography demonstrated frontal and temporal hypoperfusion with relative sparing of parietal and occipital blood flow. Previous studies suggest that the neuropathologic findings in patients with FLD are varied; some demonstrate frontal gliosis, neuronal loss, and Pick bodies while others show only gliosis and neuronal loss.

A meta-analysis of the neuropsychological sequelae of HIV infection

This meta-analysis summarizes the broad spectrum of neuropsychological research on HIV disease across a sample of 41 primary studies and an aggregate of 8,616 participants for 10 major neuropsychological ability areas. Analyses of the course of cognitive decline within and across Centers for Disease Control classifications reveals statistically significant cognitive deficits from asymptomatic HIV to AIDS. Effect sizes (Cohen, 1988) were calculated to reflect between-group (asymptomatic, symptomatic, AIDS) differences in each neuropsychological domain. Relatively small effect sizes were obtained for the asymptomatic (0.05-0.21) patients, and generally small to moderate effect sizes were obtained for symptomatic (0.18-0.65) HIV+ patients, with motor functioning exhibiting the greatest effects in this later disease stage. The most notable deficits in cognitive functioning were found in the AIDS group with moderate (attention and concentration) to large (motor functioning) effect sizes with values ranging from 0.42-0.82. Comparison of cognitive functioning as a function of disease progression revealed that motor functioning, executive skills, and information processing speed were among the cognitive domains showing the greatest decline from early to later stages of HIV. These findings indicate that cognitive deficits in the early stages of HIV are small and increase in the later phases of the illness, and that specific patterns of cognitive deficits can be detected with disease progression. These results and their clinical utility are further discussed.

A study of the Lund‐Manchester research criteria for frontotemporal dementia Clinical and single‐photon emission CT correlations

We evaluated the Lund-Manchester research criteria (LMRC) for frontotemporal dementia (FTD). With single-photon emission CT, we diagnosed 30 patients with FTD. These patients were compared with 30 with a research diagnosis of Alzheimers disease (AD). We scored every patient on each LMRC item and compared the two groups. A discriminant function showed that loss of personal awareness, hyperorality, stereotyped and perseverative behavior, progressive reduction of speech, and preserved spatial orientation differentiated 100% of FTD and AD subjects. Items relating to affect and physical findings were not different in FTD versus AD. Loss of personal awareness, eating, perseverative behavior, and reduction of speech are the LMRC items that most clearly differentiate FTD from AD.

Neuroanatomy of the self: Evidence from patients with frontotemporal dementia

Objective: To evaluate the frequency and types of change in “self” seen in frontotemporal dementia (FTD) and to determine the relative involvement of the nondominant and dominant frontal and temporal brain regions in FTD patients with or without changes in a sense of self using neuropsychology tests and neuroimaging. Background: The self has been defined as “the total, essential, or particular being of a person” involving “the essential qualities distinguishing one person from another.” Some suggest that the frontal lobes play a dominant role in maintaining the self. FTD affects anterior frontal and temporal areas and can be associated with a loss of self. Methods: Seventy-two consecutive FTD patients were evaluated with neuropsychiatric, neuropsychologic, and behavioral measures. Patients were imaged with MRI and SPECT. Charts were reviewed by a social psychologist to determine patients who exhibited a dramatic change in their self as defined by changes in political, social, or religious values. The brain areas with the most severe atrophy or hypoperfusion on neuroimaging were noted. Results: Seven of 72 patients exhibited a dramatic change in self. In six of the seven, the selective dysfunction involved the nondominant frontal region. In contrast, only one of the other 65 patients without selective nondominant frontal dysfunction showed a change in self. Conclusions: FTD patients with asymmetric loss of function in the nondominant frontal lobe often exhibit a diminished maintenance of previously learned self-concepts despite intact memory and language. Normal nondominant frontal function is important for the maintenance of the self.

Human Psychopharmacology of Hoasca, A Plant Hallucinogen Used in Ritual Context in Brazil

A multinational, collaborative, biomedical investigation of the effects of hoasca (ayahuasca), a potent concoction of plant hallucinogens, was conducted in the Brazilian Amazon during the summer of 1993. This report describes the psychological assessment of 15 long-term members of a syncretic church that utilizes hoasca as a legal, psychoactive sacrament as well as 15 matched controls with no prior history of hoasca ingestion. Measures administered to both groups included structured psychiatric diagnostic interviews, personality testing, and neuropsychological evaluation. Phenomenological assessment of the altered state experience as well as semistructured and open-ended life story interviews were conducted with the long-term use hoasca group, but not the hoasca-naive control group. Salient findings included the remission of psychopathology following the initiation of hoasca use along with no evidence of personality or cognitive deterioration. Overall assessment revealed high functional status. Implications of this unusual phenomenon and need for further investigation are discussed.

Progressive Right Frontotemporal Degeneration: Clinical, Neuropsychological and SPECT Characteristics

The behavioral, neuropsychological and single photon emission computerized tomography characteristics of 5 patients with progressive degeneration of the right hemisphere are described. In all, the brain regions with greatest involvement were right-frontal and temporal. Psychosis, compulsions and behavioral disinhibition were the dominant, and often first, symptoms. Affect was flattened and the patients seemed distant and remote. Neuropsychological testing did not reveal a consistent pattern that helped localize the abnormality to the right frontotemporal region. These patients contrast dramatically to those with left frontotemporal degeneration in whom behavior and psychiatric status is often normal. This study suggests that the right hemisphere may be primary for the control of social conduct.

Sensitivity and Specificity of Various Digit Span Scores in the Detection of Suspect Effort

ABSTRACT Digit Span Age-Corrected Scaled Score (ACSS) and Reliable Digit Span (RDS) have been suggested as effective in assessing credibility. The purpose of this study was to confirm the efficacy of suggested cutoffs for ACSS and RDS and to explore the utility of other Digit Span variables in a large sample (N = 66) of “real-world” ≥ suspect effort patients versus clinic patients with no motive to feign (N = 56) and controls (N = 32). With specificity at ≥ 90%, sensitivity of ACSS increased from 32% to 42% when a ≤ 5 cutoff was used instead of the recommended ≤ 4. The RDS recommended cutoff of ≤ 7 resulted in a sensitivity of 62% but with an unacceptably high false positive rate (23%); dropping the cutoff to ≤ 6 raised the specificity to 93% but sensitivity fell to 45%. Cutoffs for other Digit Span scores did not exceed 45% sensitivity with the exception of 50% sensitivity (11% false positive rate) for average time per digit for all attempted items > 1.0 second. A criterion of ACSS ≤ 5 or RDS ≤ 6 was associated with 51% sensitivity (91% specificity) while RDS ≤ 6 or longest string with at least one item correct ≤ 4 was associated with 54% sensitivity (88% specificity). While only moderately sensitive, Digit Span scores, including new time variables, may have a unique and effective role in the detection of suspect effort.

Utility of clinical criteria in differentiating frontotemporal lobar degeneration (FTLD) from AD

Objective To assess the ability of the current diagnostic criteria for frontotemporal lobar degeneration (FTLD) to differentiate FTLD from AD. Methods Thirty cases with autopsy-proven FTLD and 30 cases of AD, matched for Mini-Mental State Examination score, were identified from the clinical databases of three dementia subspecialty centers, and their charts were reviewed for the presence of clinical features described in the current criteria for FTLD. The proportion of patients with each clinical feature at the first clinical presentation was compared across groups. Results A significantly larger proportion of patients with FTLD showed behavioral abnormalities, particularly social and personal conduct disorders and emotional blunting, than patients with AD. Few differences in language features were seen between the groups, and many of the language features detailed in the criteria were found in only a small proportion of patients. In both groups, many patients showed neuropsychological abnormalities, except for perceptual difficulties, which were present in many patients with AD but only in a few patients with FTLD. Extrapyramidal motor symptoms were more likely to be present in FTLD. Logistic regression revealed that five features—social conduct disorders, hyperorality, akinesia, absence of amnesia, and the absence of a perceptual disorder—correctly classified 93% of patients with FTLD and 97% of patients with AD. Conclusion A combination of behavioral, neuropsychological, and physical findings is most useful in distinguishing FTLD from AD. Future studies should be directed at establishing more objective methods of identifying these clinical features.

Klinefelter syndrome: Expanding the phenotype and identifying new research directions

Purpose The purpose of this study is to summarize new data on etiology and clinical features of Klinefelter syndrome in order to derive research priorities.Methods This study was conducted using critical reviews of selective topics, emphasizing less well-recognized clinical findings.Results And Conclusions The phenotype of the prototypic 47,XXY case is well recognized: seminiferous tubule dysgenesis and androgen deficiency. Less well appreciated is the varied expressivity of 47,XXY Klinefelter syndrome, in particular neurological/cognitive perturbations like language and behavioral problems. Effective therapies are available. Reproductive technologies allow 47,XXY men to sire offspring through intracytoplasmic sperm injection (ICSI); however, genetic counseling is complex and success is low. Behavioral and expressive language difficulties are amenable to treatment by androgen therapy and psychological help. Early treatment may be imperative for optimal outcome.