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Biomedical subjects

K B Boone

Publications and source records attributed to K B Boone.

At least 19 recordsLinked to original sources
PubMed1997

Differential response of rapid eye movement sleep to cholinergic blockade by scopolamine in currently depressed, remitted, and normal control subjects.

The degree of cholinergic dysregulation of sleep in adult depression was evaluated using scopolamine. On separate sessions, placebo and scopolamine (4.5 micrograms/kg, IM) were administered to 14 patients with unipolar major depression, 16 recovered/remitted patients, and 18 normal controls. Scopolamine increased rapid eye movement (REM) latency (RL), reduced REM activity (RA), REM density (RD), and REM duration, and increased the percentage of stage 4 sleep in all groups. There was a differential effect of scopolamine on RL, RA, and REM duration for the first REM period, and on percentage of stage 4 sleep. Whereas a primary cholinergic hyperactivity could account for the RA and RD responses, the response profile for RL was more compatible with reduced aminergic tone as the proximal cause of the cholinergic hyperactivity. Whether the sleep abnormalities observed in remitted patients reflect an underlying vulnerability for development or recurrence of depression, and/or a scar, remains to be determined.

Adult↗
PubMed1997

Abnormal ACTH and prolactin responses to fenfluramine in rats exposed to single and multiple doses of MDMA.

The present study examined the persistent functional consequences associated with exposure to single and multiple doses of (+/-) 3,4-methylenedioxymethamphetamine (MDMA) as reflected by the neuroendocrine responses to d,l-fenfluramine (FEN). Adult male rats were administered a single dose of MDMA (20 mg/kg, s.c.) and challenged 2 weeks later with saline or FEN (2, 4, 6 and 8 mg/kg, s.c.). The corticotropin (ACTH) response to FEN (6 and 8 mg/kg) was blunted and the prolactin response to FEN (4 and 6 mg/kg) was enhanced in MDMA pre-treated rats. The ACTH and prolactin responses to FEN (6 mg/kg, s.c.) were then evaluated 4, 8 and 12 months after exposure to single and multiple doses MDMA (20 mg/kg, s.c. and 20 mg/kg, s.c., bid, x 4 days, respectively). The ACTH response to FEN was significantly reduced at 4 and 8 months in both MDMA treatment groups, and at 12 months in the multiple dose group only. In contrast, the prolactin response to FEN was enhanced in both groups of MDMA treated rats at 4 months, but only in the multiple dose group at 8 months. By 12 months, the prolactin response to FEN had normalized. Following multiple doses of MDMA, 5-HT concentrations were reduced significantly in the frontal cortex at 4 and 12 months. The results indicate that exposure to single or multiple doses of MDMA can produce functional alterations which can persist for months, whereas the biochemical sequelae were less robust and shorter lived.

Adrenocorticotropic Hormone↗
PubMed1996

Neuropsychological deficits among older depressed patients with predominantly psychological or vegetative symptoms.

Depressed outpatients having primarily psychological or vegetative symptoms, as defined by the factor analytically developed Hamilton Depression Scale superfactors described by Rhoades and Overall (1983), were compared with similarly aged normal controls on a comprehensive neuropsychological battery. The vegetative group evidenced poorer performance than controls on several measures associated with right hemisphere functioning and on a task associated with executive functioning. In contrast, the psychological group did not significantly differ from controls on any measure, and had significantly better performance than the vegetative group on several tasks. These findings suggest that neuropsychological deficits associated with depression may be limited to those patients with primarily vegetative symptoms.

Aged↗
PubMed1996

Comparison of neuropsychological functioning in Alzheimer's disease and frontotemporal dementia.

Neuropsychological changes distinguishing mild Alzheimer's disease (AD) from frontotemporal dementia (FTD) have been described, but empirical verification of differential cognitive characteristics is lacking. Archival neuropsychological data on 15 FTD patients, 16 AD patients, and 16 controls were compared. Controls outperformed both patient groups on measures of verbal and nonverbal memory, executive ability, and constructional skill, with AD patients showing more widespread memory decline. No differences were found between the 3 groups in confrontation naming, recognition memory, or basic attention. Patient groups differed only in nonverbal memory, with FTD patients performing significantly better than AD patients. However, patient groups also differed in pattern of performance across executive and memory domains. Specifically, AD patients exhibited significantly greater impairment on memory than executive tasks, whereas the opposite pattern characterized the FTD group. These findings suggest that examination of relative rankings of scores across cognitive domains, in addition to interpretation of individual neuropsychological scores, may be useful in differential diagnosis of FTD versus AD.

Aged↗
PubMed1996

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.

Adult↗
PubMed1996

Cognition and white matter hyperintensities in older depressed patients.

OBJECTIVE: The authors compared amounts of white matter hyperintensity in late- and early-onset depressed patients and never-depressed older subjects, compared neuropsychological function in these groups, and investigated the association between white matter hyperintensities and cognitive function in depression. METHOD: Sixty currently depressed patients whose first depression occurred after age 50 years, 35 depressed patients over age 50 whose first depression occurred before age 35, and 165 nonpsychiatrically ill subjects over age 50 underwent magnetic resonance imaging (MRI) and neuropsychological evaluation. Areas of white matter hyperintensity were measured from MRI images. RESULTS: The late-onset patients had more white matter hyperintensity than either of the other groups. Compared to the nondepressed subjects, the patients had significantly lower scores in the cognitive domains of nonverbal intelligence, nonverbal memory, constructional ability, executive ability, and information processing speed. The cognitive abnormalities were mostly confined to the late-onset patients, and the presence of a large amount of white matter hyperintensity was associated with significantly poorer executive skills. However, most of the scores were not in the significantly impaired range. CONCLUSIONS: Large amounts of white matter hyperintensity are more frequent in patients with late-onsetdepression than in elderly subjects with early-onset or no depression. Both late- and early-onset elderly depressed patients show mild decrements in some "right hemisphere" cognitive skills; the late-onset subjects also show deterioration in information processing speed and executive functions. Patients with large amounts of white matter hyperintensity have significantly poorer executive function.

Age Factors↗
PubMed1995

Rey 15-item memorization and Dot counting scores in a "stress" claim worker's compensation population: relationship to personality (MCMI) scores.

The relationship between apparent faking of cognitive impairment (as detected by such "malingering" tests as 15-item Memorization and Dot Counting) and faking of psychiatric symptoms has not been investigated formally. In addition, no empirical literature is available on the relationship between personality traits and faking of cognitive symptoms. Of 154 subjects who claimed "stress" psychiatric injury, 12% appeared to be faking cognitive impairment; 4.5% failed the 15-item Memorization Test, and 10% failed the Dot Counting task. Faking of cognitive symptoms occurred in only 23% of subjects who were faking/exaggerating psychological symptoms on the MCMI. Malingering test failure was associated with significant elevations on MCMI personality scales, although this appeared to be an artifact of attempts to fake/exaggerate on the MCMI, rather than a reflection of "true" personality traits.

Adolescent↗
PubMed1994

Reduction of cerebral blood flow in older depressed patients.

BACKGROUND: We investigated regional cerebral blood flow in older, drug-free depressed patients and examined factors that might be related to rCBF. METHODS: We studied 39 physically healthy depressed patients over the age of 50 years and 20 psychiatrically healthy control subjects. Regional cerebral blood flow was measured with single photon emission computed tomography, using both xenon 133 (to quantify regional cerebral blood flow) and 99mTc-hexamethylpropylene amine oxime (to make regional comparisons). From magnetic resonance imaging, we derived a semiquantitative measure of areas of white matter hyperintensity and a ventricle-to-brain ratio. RESULTS: Patients exhibited a global reduction in regional cerebral blood flow compared with controls, with the orbital frontal and inferior temporal areas affected bilaterally. Regional cerebral blood flow was also reduced in higher brain slices in the right but not the left hemisphere. Significant predictors of lowered regional cerebral blood flow were being depressed, being male, and having a greater ventricle-to-brain ratio. There appeared to be a subgroup of patients who demonstrated large areas of white matter hyperintensity and low regional cerebral blood flow. CONCLUSIONS: Cerebral blood flow was lower in older, medication-free depressed patients than in age-matched control subjects, involved the orbital frontal and anterior temporal regions, and was more reduced in the right hemisphere.

Age Factors↗
PubMed1994

Cognitive deficits and personality patterns in maternally versus paternally inherited myotonic dystrophy.

Neuropsychological functioning was compared between 7 myotonic dystrophy (MD) patients with maternal inheritance (mMD), 14 MD patients with paternal (pMD) inheritance, and 10 normal controls. Both groups evidenced slowed performance on a measure of information processing speed. However, the pMD group had an otherwise normal neuropsychological profile. In contrast, the mMD group exhibited abnormal scores on measures of intelligence, visual-construction, and some, albeit not all, measures of frontal functioning. No significant differences between the three groups were detected on measures of verbal or visual memory, or on measures of visual-perception. Overall, these findings suggest that inheritance pattern is one important moderating variable in determining the impact of the MD gene on cognitive functioning. Personality assessment revealed a relatively high incidence of dependent tendencies and depressive symptoms, even among pMDs. Given the generally normal cognitive functioning among pMDs, personality/emotional disturbance observed among MD patients may largely reflect their adjustment to having a progressively disabling medical condition, rather than being a direct expression of MD related brain dysfunction.

Adult↗
PubMed1994

Cognitive functioning in a mildly to moderately depressed geriatric sample: relationship to chronological age.

The neuropsychological performance of three age cohorts of depressed patients (46-59, 60-69, and 70-85) was compared with the performance of age-matched control subjects to determine whether advancing age potentiates the effect of depression on cognition. Depression and increasing age did not interact to produce more pronounced cognitive deterioration in our unmedicated, medically healthy, well-educated outpatients diagnosed with mild to moderate major depression. Test findings suggest that presence of mild to moderate depression may result in premature "aging" of specific cognitive abilities (such as nonverbal memory, word generation, and categorization), but once the seventh decade is reached, cognition in depressed and nondepressed individuals appears to be comparable.

Age Factors↗
PubMed1993

Wisconsin Card Sorting Test performance in healthy, older adults: relationship to age, sex, education, and IQ.

We obtained Wisconsin Card Sorting Test (WCST) scores on 91 (35 male and 56 female) healthy, well-educated individuals aged 45 to 83. Women scored better than men on six WCST scores (categories, errors, perseverative responses, % perseverative errors, % conceptual level responses, and trials to first category), while subjects with more than 16 years of education outscored those limited to high school education on four measures (perseverative responses, errors, % perseverative errors, % conceptual level responses). Individuals older than 70 years of age scored less well than younger subjects on only two indices (errors, % conceptual level responses). Full Scale IQ was not related to WCST scores. Our findings suggest that WCST scores should be interpreted within the context of patient gender, education, and age.

Age Factors↗
PubMed1993

Brain imaging in late-life schizophrenia and related psychoses.

Despite disagreements about nomenclature, patients who develop schizophrenic or schizophrenia-like symptoms in later life are often seen in clinical practice. Questions about the etiology of late-life psychotic disorders and about their similarities or differences from early-onset disorders remain unanswered. Neuro-imaging techniques have been used to study patients with late onset of psychosis, and in substantial subgroups of patients (from 25% to 100% in various studies) compared with age-matched control subjects, structural and functional abnormalities have been found. We review the literature on imaging in late-life schizophrenia and related psychotic disorders, and we present data from our own investigations of patients with these disorders. We discuss the potential usefulness of imaging evaluations in patients with late-onset disorders, and we offer suggestions for future investigations.

Aged↗
PubMed1992

Neuropsychological correlates of white-matter lesions in healthy elderly subjects. A threshold effect.

The clinical significance of white-matter lesions (WMLs) detected by computed tomography and magnetic resonance imaging in healthy elderly subjects has been controversial, with some studies reporting associated deficits in cognition and others failing to document cognitive disturbance. In our sample of 100 healthy elderly individuals, almost half (n = 46) had no WMLs, approximately one fourth had minimal (less than or equal to 1 cm2; n = 27) or moderate (greater than 1 cm2 but less than or equal to 10 cm2; n = 21) WML areas, and six subjects had large WML areas (greater than 10 cm2). Substantial disturbances in basic attention and selected frontal lobe skills were detected in the six subjects with the large WML areas. These findings suggest that a "threshold" of WML area must be present before cognitive deficits are observed. Surprisingly, no significant relationships between duration of hypertension or cholesterol levels and WMLs were detected, suggesting that factors other than vascular disturbances are involved in the origin of at least some WMLs.

Aged↗
PubMed1991

Brain injury and cognitive function in late-onset psychotic depression.

Fourteen patients who developed a psychotic depression after age 45 were compared with 72 non-psychiatrically ill elderly control subjects using neuroimaging and neuropsychological (NP) tests. Despite the fact that the patients were not studied if they had an obvious dementia or neurological disease, structural brain abnormalities were found in approximately two-thirds of patients and in less than 10% of controls. The most common abnormality, subcortical white matter (WM) lesions, was thought to be vascular in etiology. Also, tumor and primary degenerative dementia were found more frequently in the patients. Compared to an age-, sex-, and education-matched control group, the patients performed more poorly on NP tests of frontal lobe, memory, and visual spatial abilities. Diagnostic evaluation of the patient with late-onset psychotic depression should include computed tomography or magnetic resonance imaging as structural brain abnormalities are common in these patients.

Age of Onset↗
PubMed1991

Brain lesions and cognitive function in late-life psychosis.

Twenty-four patients who developed their first psychotic episode after the age of 45 were studied with MRI and comprehensive neuropsychological testing and compared with 72 healthy elderly subjects. The patients demonstrated more clinical abnormalities on MRI, were more likely to have large white-matter lesions or metabolic illness, and did more poorly on many neuropsychological tests, particularly those testing frontal-lobe and memory abilities. We conclude that structural brain injury is commonly associated with the late onset of psychosis. Neuroimaging investigations are a valuable component in the evaluation of this patient group.

Aged↗
PubMed1989

Seashore Rhythm Test performance in patients with unilateral temporal lobe damage.

The Seashore Rhythm Test has been reported to be sensitive to right hemisphere dysfunction and, in particular, right temporal lobe integrity. However, several reports have appeared that have failed to support these earlier findings. In the latter studies, the confounding effects of possible bilateral or extratemporal lobe dysfunction in the patient groups could not be ruled out. The present study investigated the Seashore Rhythm Test performance of 38 right-handed seizure patients with evidence of glucose hypometabolism restricted to the right (n = 23) or left (n = 15) temporal lobe on positron computed tomography. Patients were studied prior to and subsequent to unilateral anterior temporal lobectomy for control of medically intractable seizures. No significant difference was found between right and left temporal lobe dysfunctional patients, either pre- or post-lobectomy, which further corroborates that the Seashore Rhythm Test does not discriminate between patients with right vs. left temporal lobe damage.

Adult↗