Neuropsychiatry, neuropsychology, and behavioral neurology最新文献

Objective: To determine the cognitive effects of daily repetitive transcranial magnetic stimulation (rTMS) administered under the conditions of a treatment trial for major depression.

Background: Although daily left dorsal prefrontal rTMS has improved mood in some patients with treatment-refractory depression, potential cognitive side effects of extended daily treatment have not been systematically studied.

Method: In a randomized double-blind treatment study, 10 subjects (mean age, 42 +/- 15 years) with an episode of major depression received either 2 weeks of low-frequency (1 Hz) or high-frequency (20 Hz) rTMS (800 pulses, 20 trains over 20 minutes, 80% of motor threshold, 5 days per week) to the left dorsolateral prefrontal cortex and then were crossed over to the other treatment condition. Patients received cognitive testing at baseline and after the first and second weeks of low- or high-frequency rTMS, which was examined by repeated-measures ANOVA.

Results: Of 16 cognitive measures tested after 1 or 2 weeks of rTMS compared with baseline status, none showed deterioration, and the only significant main treatment effect indicated improvement on a list-recall test from pre- to post-rTMS after 1 week (p <0.05).

Conclusions: These preliminary data suggest no gross deleterious cognitive effects of 2 weeks of 1- or 20-Hz rTMS at 80% of motor threshold over the left prefrontal cortex. Further cognitive studies of the effects of rTMS at other parameters used in clinical trials for mood disorders remain to be undertaken.

Objective: Simple and complex visuomotor performance of the right and left sides of the body was investigated in 37 children with left hemisphere lesions, 35 children with right hemisphere lesions, 53 developmentally dyslexic children, 29 developmentally hyperactive children, and 35 "normal" children who had endured a very mild head injury with no sequelae.

Background: Lateralized soft signs, EEG topography, metabolic brain imaging, and neuropsychological test profiles suggest a predominance of left hemisphere dysfunction in dyslexia and right hemisphere dysfunction in hyperactivity.

Method: Nine measures of lateralized performance were drawn from the Purdue pegboard, Letter cancellation, Rey complex figure, Wechsler Intelligence Scale for Children (WISC) Mazes, and WISC Picture completion tests.

Results: The children with left hemisphere lesions manifested significantly weaker performance on test components involving the right body side, relative to the normal controls, on the Purdue pegboard, Rey complex figure (delayed recall condition), and WISC Picture completion tests, and the dyslexic children on the former two. The children with right hemisphere lesions manifested significantly weaker performance on test components involving the left body side, relative to the normal controls, on the WISC Mazes test, as did the hyperactive children.

Conclusions: We propose that (1) contralateral performance decrement results from a unilateral cortical lesion in children, and (2) developmental dyslexia may comprise a slight predominance of left hemisphere dysfunction and developmental hyperactivity of right hemisphere dysfunction.

Objective: The neurocognitive sequelae of therapeutic cranial irradiation are not well characterized in adults with primary brain tumors. To address this problem, we prospectively examined neuropsychological findings during two phases of radiation effects.

Background: Investigations of radiation effects have revealed variable outcomes that range from no radiation-associated morbidity to severe cognitive impairment, but have relied on case reports or retrospective studies of late-delayed changes in white matter or in cognition. No reliable radiographic or neurocognitive tools exist to describe the multiple phases of radiation effects.

Method: Twenty adult patients (median age, 39 years) from a university hospital were treated with radiotherapy (RT) for low-grade primary brain tumors. Prospective longitudinal neuropsychological studies were compared at baseline (after surgery and before irradiation) and at 3, 6, and 12 months after RT to examine early-delayed effects, including verbal memory changes in 20 patients and visual memory changes in 11 patients. We also examined cognitive changes during the late-delayed phase for up to 3 years after RT and determined whether early-delayed memory deficit predicted late-delayed memory deficit in a small subset of patients. A comprehensive neuropsychological battery was used, including verbal and visual memory tests designed to compare learning, storage, and retrieval.

Results: Patients demonstrated normal verbal memory at baseline, decrement, and then rebound in verbal retrieval. Deficit at baseline and recovery up to 1 year after RT defined visual memory. Together, these observations constitute a double dissociation of memory functions. No changes over time were observed in other neurocognitive tests or in fatigue or mood measures. Time-dependent patterns of each long-term memory test were examined in relation to lesion site in individual patients.

Conclusions: The double dissociation of memory functions after RT may provide markers for the damaging and facilitative early-delayed effects of RT. Late-delayed effects were not predicted based on early-delayed changes in a small sample.

Objective: The purpose of this study was to evaluate symptoms associated with impaired insight in patients with Alzheimer disease (AD).

Background: Although unawareness of deficits is common in AD, the relation of awareness to psychiatric and behavioral disturbances has not been extensively studied.

Method: We conducted a cross-sectional investigation of 91 patients with probable AD according to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association. Awareness of cognitive and functional deficits was measured with the Inaccurate Insight item from the Neurobehavioral Rating Scale. Psychiatric and behavioral symptoms were measured using factor scores and individual items from the Neurobehavioral Rating Scale. Global cognitive deficits were measured using the Mini-Mental State Examination (MMSE).

Results: Stepwise regression analysis showed that insight was associated with MMSE score, depression/anxiety factor score, and agitation/disinhibition factor score. Variables not associated with awareness of deficits included patient age, behavioral retardation factor score, verbal output disturbance factor score, and psychosis factor score. Post hoc analyses showed a positive relation (i.e., greater insight, more symptomatology) between deficit awareness and symptoms of depressed mood and anxiety. There was a negative relation (i.e., greater insight, less symptomatology) between insight and symptoms of hostility, agitation, inattention, and tension. In a follow-up stepwise regression analysis, increased deficit awareness was associated with a higher MMSE score, greater depressed mood, and decreased agitation.

Conclusions: These findings suggest that patients with AD may experience symptoms of depressed mood in relation to increased awareness of decrements in functioning. The data also indicate that patients with poor insight demonstrate greater agitated behavior. Consistent with previous research, impaired insight was higher in the later stages of the illness.

Objective: This goal of this study was to evaluate reading ability by assessing eye movements during reading among patients with Alzheimer disease (AD) compared with normal elderly controls.

Background: Reading is disturbed in patients with AD. These patients may have changes in reading ability early in the course of their disease before clinical alexia or abnormalities are apparent on standard reading tasks.

Method: Reading competence was evaluated by recording eye movements during reading in 14 patients with mild to moderate clinically probable AD and 14 age- and education-matched controls.

Results: All patients with AD could recognize letters and words and could understand written material of similar difficulty. Despite successful reading comprehension among the patients with AD, their oculographs showed slowed reading and irregular eye movements. Compared with controls, the patients with AD did not differ in saccadic duration; however, they had significantly longer fixation times, more forward saccades per line of text, and more saccadic regressions. In addition, increased reading difficulty significantly correlated with a scale of dementia severity in the patients with AD.

Conclusions: This pattern of eye movements corresponds to increased text difficulty and probably represents difficulty with lexical-semantic access in AD. These results suggest that disordered eye movements can signal difficulties in reading ability in AD even before complaints of reading difficulty or abnormalities on reading tests and may be a means of identifying linguistic impairment early in this disorder.

Objective: We conducted a follow-up study on a patient with enduring psychic shock-induced cognitive impairment to study by neuropsychological and functional imaging methods the degree of his recovery process on the brain and cognitive levels.

Background: Based on the assumption that trauma and stress conditions can alter the functions of the nervous systems, we report on a patient whom we studied 2 and 12 months after he suffered "mnestic block syndrome" and additional cognitive deterioration symptoms.

Methods: We report on a patient studied 2 and 12 months after he suffered "mnestic block syndrome" and additional cognitive deterioration symptoms. Magnetic resonance imaging and fluorodeoxyglucose positron emission tomography were used for neural and detailed neuropsychological testing for cognitive deficits.

Results: The patient initially manifested severe intellectual decline, including severe anterograde and retrograde amnesia. His symptoms were correlated with major, although selective, reductions in his brain metabolism (2-3 SD below those of controls). Presently, he shows a normal brain metabolism and has regained parts of his memory and many of his other intellectual capabilities. Nevertheless, he still has long-term memory impairments.

Conclusions: This case demonstrates a close relation between brain metabolism and cognitive performance, with major deficits of both at 2 months and major recovery of both at 12 months after a shocking event. It can serve as an example for possible stress-related deteriorations in certain brain regions, which can be partly corrected by psychotherapeutic interventions, passing time, and favorable environmental conditions.

Objective: We postulated that disruption of callosal pathways as occurs in Marchiafava-Bignami disease (MBD) is associated with marked impairment in brain functioning as measured by cognitive assessment and neuroimaging.

Background: MBD is considered to be a rare and severe complication of chronic alcoholism. It is characterized by necrosis and subsequent atrophy of the corpus callosum, which is the major brain structure connecting corresponding areas of both hemispheres.

Methods: We review the existing literature on MBD with respect to conceptualization, theories of pathogenesis, forms of the disease, and neuroimaging and neuropsychological findings. We then present the case of a middle-aged man with MBD who underwent extensive clinical, neuropsychological, and neuroimaging studies.

Results: Neuropsychological evaluation revealed a pattern of severe global dementia. Magnetic resonance imaging showed moderate atrophy of anterior callosal regions and severe atrophy of posterior callosal regions in the setting of cortical and subcortical atrophy. Resting metabolism positron emission tomography revealed decreased glucose metabolism most pronounced in subcortical and mesial frontal regions. The differential diagnosis, function of the corpus callosum, and potential limitations of our case study are discussed.

Conclusions: On account of the history, clinical presentation, and results of magnetic resonance imaging of the brain, we diagnosed our patient with chronic MBD.

Objective: The relation of perinatal complications to metabolism of orbitofrontal cortex was studied in 12 normal adolescents aged 13 to 17 years.

Background: Perinatal complications are associated with both (a) behavioral signs of frontal lobe dysfunction and (b) increased risk for mood disorders and schizophrenia. Perinatal complications are not usually sufficient to produce these disorders, however, suggesting an etiologic model in which perinatal complications interact with a second, familial, liability factor. The present study tested a key prediction of this "two-factor" model, namely, that perinatal complications will be associated with physiologic signs of frontal dysfunction, even in persons who have no personal or family history of these psychiatric disorders.

Methods: Subjects were screened by structured interviews with the Kiddie Schedule for Affective Disorders and Schizophrenia and had no personal or family history of psychiatric disorder. Ratios of choline and N-acetyl aspartate to creatine in orbitofrontal cortex were measured using proton magnetic resonance spectroscopy. Perinatal complications were scored with the examiners blinded to magnetic resonance spectroscopy data, applying published scales to hospital records on subjects' gestations and births.

Results: Perinatal complications were significantly correlated with reduced concentrations of choline and N-acetyl aspartate.

Conclusions: Our results complement earlier findings of significant relations between perinatal complications and signs of frontal lobe dysfunction, as well as elevated rates of these two types of variables in mood disorders and schizophrenia.

Objective: The objectives of this study were to examine common patterns in the lives and artwork of five artistic savants previously described and to report on the clinical, neuropsychological, and neuroimaging findings from one newly diagnosed artistic savant.

Background: The artistic savant syndrome has been recognized for centuries, although its neuroanatomic basis remains a mystery.

Methods: The cardinal features, strengths, and weaknesses of the work of these six savants were analyzed and compared with those of children with autism in whom artistic talent was absent. An anatomic substrate for these behaviors was considered in the context of newly emerging theories related to paradoxical functional facilitation, visual thinking, and multiple intelligences.

Results: The artists had features of "pervasive developmental disorder," including impairment in social interaction and communication as well as restricted repetitive and stereotyped patterns of behavior, interest, and activities. All six demonstrated a strong preference for a single art medium and showed a restricted variation in artistic themes. None understood art theory. Some autistic features contributed to their success, including attention to visual detail, a tendency toward ritualistic compulsive repetition, the ability to focus on one topic at the expense of other interests, and intact memory and visuospatial skills.

Conclusions: The artistic savant syndrome remains rare and mysterious in origin. Savants exhibit extraordinary visual talents along with profound linguistic and social impairment. The intense focus on and ability to remember visual detail contributes to the artistic product of the savant. The anatomic substrate for the savant syndrome may involve loss of function in the left temporal lobe with enhanced function of the posterior neocortex.

Objective: To delineate regions involved in visual word recognition.

Background: The processes and regions involved in visual word recognition have been somewhat controversial for over 100 years.

Methods: This study used regional cerebral blood flow as assessed by functional magnetic resonance imaging to study normal subjects (N = 9) on an individual within-subject basis while they were actively engaged on-line in a visual lexical decision task. Standard analysis techniques were used for identifying regions of activation.

Results: Across subjects, the task activated a number of regions, including the occipital pole, lateral and basal occipitotemporal (including lingual and fusiform) regions, superior and middle temporal gyri, and supramarginal and angular gyri. Typically, these regions were activated bilaterally; when activation was unilateral, it was on the left. Some of the areas activated (e.g., inferior parietal regions) have not been previously reported to be involved in such types of processing by activation studies but have been implicated in lesion studies.

Conclusions: These results broaden the areas known to be involved in visual word recognition. The bilateral activation associated with visual word recognition is in some respects analogous to the "what" system in visual recognition described in subhuman primates. In addition, the study raises several methodologic issues. The within-subject analysis showed variability in the specific regions activated when subsequently comparing across individuals, raising implications for future functional imaging studies.