Oscillatory Activities in Multiple Frequency Bands in Patients with Schizophrenia During Motion Perception.

Patients with schizophrenia show impairment in binding stimulus features into coherent objects, which are reflected in disturbed oscillatory activities. This study aimed to identify disturbances in multiple oscillatory bands during perceptual organization of motion perception in patients with schizophrenia. EEG was recorded from healthy controls and patients with schizophrenia during continuous presentation of a motion stimulus which induces reversals between two exogenously generated perceptions. This stimulus was used to investigate differences in motion binding processes between healthy controls and patients with schizophrenia. EEG signals were transformed into frequency components by means of the Morlet wavelet transformation in order to analyse inter-trial coherences (ITC) in the delta (1-4 Hz), theta (4-7 Hz), alpha (8-12 Hz), and gamma (28-48 Hz) frequency bands during exogenous motion binding. Patients showed decreased delta-ITC in occipital and theta-ITC in central and parietal areas, while no significant differences were found for neither alpha nor gamma-ITCs. The present study provides one of the first insights on the oscillatory synchronizations related with the motion perception in schizophrenia. The ITC differences revealed alterations in the consistency of large-scale integration and transfer functions in patients with schizophrenia.

What does the broken brain say to the neuroscientist? Oscillations and connectivity in schizophrenia, Alzheimer's disease, and bipolar disorder.

The application of the concept and methods of brain oscillations has been an important research area in neurosciences. In the last decades, besides the application in cognitive processes, the study of changes in brain oscillations in diseases has also become an important focal point of research. In the present paper, some remarkable examples in three different diseases are taken into consideration: 1) schizophrenia (SZ), 2) Alzheimer's disease (AD), 3) bipolar disorders (BD). In the current literature, decreased oscillations in cortical recordings are observed in most of the pathologies. For example, decrease of gamma activity in SZ, decrease of delta activity in almost all diseases, as well as frequency shifts in alpha and the lower frequencies were recorded. However, there are also paradoxical cases in which an increase of oscillatory activities is observed. In BD, whereas alpha activity is greatly decreased, a huge increase of beta activity is observed. Or, in SZ, a paradoxical increase of gamma activity can be observed during cognitive loading. We also observed paradoxical changes in the analysis of connectivity. In AD, we find that alpha, delta, and theta coherences between distant parts of the cortex are greatly decreased, whereas in the gamma band, event-related coherences attain very high values. The comparison of the results and paradoxical changes in diseases may lead to important conclusions related to the web of oscillations and neurotransmitters. In turn, we could gain new insights to approach "brain function", in general.

New rather than old? For working memory tasks with abstract patterns the P3 and the single-trial delta response are larger for modified than identical probe stimuli.

Memory-guided decision making is dynamic and context-dependent, even though many studies describe an enhancement of the P3 for recognized items in memory tasks ("old-new effect"). This study utilized a delay-dependent working memory task during which decision making could be optimized by focusing attention on detected changes instead of recognized similarities. Mean P3 amplitude and delta activity were analyzed from participants who classified probe stimuli as identical or modified. The P3 amplitudes were larger for modified than for identical probes, even when the probe occurred 4,000 ms after the primary stimulus. Enhanced single-trial amplitude, trial-by-trial consistency, and frontoparietal phase coherence of delta activity contributed to the larger P3 for the modified probe. Thus, context-dependent attentional resource allocation supporting memory-guided decisions might explain the enhancement of the P3 for specific probe types.

Altered oscillatory alpha and theta networks in schizophrenia.

In the present study we used a simple visual evoked potential and a visual oddball paradigm to investigate alterations in the temporal integration of different frequency components such as alpha and theta oscillations in patients with schizophrenia. We found that neither the amplitude enhancement after stimulus onset nor the intertrial phase coherence was generally reduced in patients, but that the topography of the neural response was altered. While healthy controls elicited their maximum early alpha as well as late theta response over posterior electrode sites, the maximum response in patients was shifted to anterior electrode positions. This result was not found for the late theta response for targets as target processing was accompanied with frontal theta amplitude enhancement in healthy controls as well. The change of the topographical response pattern was mirrored by the intertrial phase coherence in both frequency bands. The findings imply that schizophrenia is related to multiple alterations in oscillatory networks. Even during simple tasks without high cognitive demands dysfunctional mechanisms of temporal and regional coordination appear to be of importance in schizophrenia.

Multiple fire ant stings: report of 3 cases and review of the literature.

Imported fire ant sting reactions are becoming an increasing problem in the United States. It is important for clinicians to be familiar with their possible cutaneous and noncutaneous presentations. We present 3 cases with multiple fire ant stings, followed by a review of the literature.

Periorbital edema as the presenting sign of juvenile dermatomyositis.

We report a case of juvenile dermatomyositis that presented with periorbital edema. Dermatomyositis is an autoimmune disorder with cutaneous manifestations including heliotrope patches, Gottron's papules, periungual telangiectasisas, and subcutaneous calcifications. Periorbital edema may accompany the classic heliotrope rash and, as in this case, may be the only presenting sign of juvenile dermatomyositis.

Skin biopsy techniques for the internist.

OBJECTIVE: To review three commonly performed skin biopsy procedures: shave, punch, and excision. DATA SOURCES: English-language articles identified through a MEDLINE search (1966-1997) using the MeSH headings skin and biopsy, major dermatology and primary care textbooks, and cross-references. STUDY SELECTION: Articles that reviewed the indications, contraindications, choice of procedure, surgical technique, specimen handling, and wound care. DATA EXTRACTION: Information was manually extracted from all selected articles and texts; emphasis was placed on information relevant to internal medicine physicians who want to learn skin biopsy techniques. DATA SYNTHESIS: Shave biopsies require the least experience and time but are limited to superficial, nonpigmented lesions. Punch biopsies are simple to perform, have few complications, and if small, can heal without suturing. Closing the wound with unbraided nylon on a C-17 needle will enhance the cosmetic result but requires more expertise and time. Elliptical excisions are ideal for removing large or deep lesions, provide abundant material for many studies, and can be curative for a number of conditions, but require the greatest amount of time, expertise, and office resources. Elliptical excisions can be closed with unbraided nylon using a CE-3 or FS-3 needle in thick skin or a P-3 needle on the face. All specimens should be submitted in a labeled container with a brief clinical description and working diagnosis. CONCLUSIONS: Skin biopsies are an essential technique in the management of skin diseases and can enhance the dermatologic care rendered by internists.

Chronic venous insufficiency and venous ulceration.

OBJECTIVE: To review and summarize the literature on the normal venous circulation of the leg, and the epidemiology, pathophysiology, and treatment of chronic venous insufficiency (CVI). DATA SOURCES: English-language articles identified through a MEDLINE search (1966-1996) using the terms venous insufficiency or varicose ulcer and epidemiology, pathophysiology, diagnosis, and clinical trial (pt), and selected cross-references. STUDY SELECTION: Articles on epidemiology, pathophysiology, and treatment of CVI. Randomized, controlled studies were specifically sought for treatment efficacy. DATA EXTRACTION: Data were manually extracted from selected studies and reviews: emphasis was placed on information relevant to the general internist. DATA SYNTHESIS: Chronic venous insufficiency is a common primary care problem associated with significant morbidity and health care costs. The clinical spectrum of disease ranges from minor cosmetic concerns to severe fibrosing panniculitis and ulceration. Duplex Doppler ultrasonography may be the single best test to rule out deep venous thrombosis and other entities that can mimic CVI. Leg elevation and compression stockings are effective treatments for CVI; recalcitrant cases may require intermittent pneumatic compression. Topical antiseptics, antibiotics, enzymes, or growth factors offer no clear advantages in ulcer healing. Ulcer dressings remain a matter of convenience, cost, and physician judgment. The role of surgery in CVI appears to be limited. CONCLUSIONS: Chronic venous insufficiency is a recalcitrant, recurrent medical problem. This condition can be managed by primary care physicians with relatively inexpensive treatment modalities in association with lifestyle modification.

Disseminated histoplasmosis in a patient with sarcoidosis: a controversial relationship and a diagnostic dilemma.

The diagnosis of sarcoidosis in patients with disseminated histoplasmosis remains controversial. It has been suggested that the immune abnormalities in sarcoidosis predispose one to disseminated histoplasmosis. Two cases have been reported that indicate a possible relationship between the two diseases. This is a case of sarcoidosis complicated with disseminated histoplasmosis in which the controversial relationship between the two diseases is emphasized and the available medical literature is reviewed.

Occlusal force after partial mandibular resection.

Surgical resection of a segment or loss of mandibular continuity can adversely affect most of the structures essential for maximum occlusal force. Five subjects who had partial mandibular resections for treatment of squamous cell carcinoma were studied. Occlusal force was recorded before and after cancer treatment and following prosthetic rehabilitation. A gnathodynamometer was used to record anterior occlusal force. Five edentulous and five dentate cancer-free subjects matched for age were studied to establish comparable normative data. The null hypothesis that partial mandibular resection would not affect maximum occlusal force was rejected (p = 0.0101). Mandibular resection did alter maximum occlusal force. The impact of the decrease in maximum occlusal force on masticatory function is yet to be determined.

Masticatory function in hemimandibulectomy patients.

Surgical resection of a segment or loss of continuity of the mandible can adversely affect most of the structures essential for mastication. Five subjects who had hemimandibular resections for cure of squamous cell carcinoma were studied. Masticatory function tests were conducted pre- and post-surgery and post-prosthetic rehabilitation. A 0.5-g Frito corn chip served as the test food, and a sieve analysis was used to evaluate swallowing threshold and masticatory performance. Ten controls were studied in order to determine corresponding normative scores. Post-surgery results indicate that the extent of mandibular resection and loss of continuity tend to decrease masticatory function. The time required to perform the mastication test, and the number of strokes required to achieve swallowing threshold were increased. Prosthetic rehabilitation did improve masticatory function in some patients. Loss of mandibular continuity may not be an absolute predictor of decreased masticatory function.

Longitudinal nail biopsy in evaluation of acquired nail dystrophies.

We reviewed longitudinal nail biopsies performed at Henry Ford Hospital on patients with acquired nail dystrophies to see whether the procedure did, indeed, provide useful diagnostic information and to see which microscopic features were most helpful in histopathologic diagnosis. Clinical diagnoses included psoriasis, lichen planus, Darier's disease, isolated longitudinal defects, and diffuse thickening. We found that clinical diagnosis could be supported by histopathologic findings in eight of twenty cases of acquired nail dystrophy. Specifically, we were able to make a diagnosis of psoriasis in four cases, lichen planus in three cases, and Darier's disease in one case. The other twelve cases showed nonspecific eczematous changes. We conclude that the longitudinal nail biopsy may be a useful diagnostic tool in certain cases of acquired nail dystrophy.

Pityriasis rotunda: two cases in black Americans.

Pityriasis rotunda is an uncommon cutaneous disorder consisting of asymptomatic, perfectly circular, scaling plaques on the trunk and extremities. Histopathologic findings are consistent with ichthyosis vulgaris. The majority of cases are seen in association with an underlying disease, and most authors believe that this entity represents a form of acquired ichthyosis. Previous cases have been restricted to certain geographic and ethnic groups (most commonly Japanese and South African Bantu). We report two cases of pithyriasis rotunda, both occurring in black Americans. We believe that these are the first reported cases seen in Americans.

Seborrheic dermatitis in patients with acquired immunodeficiency syndrome.

Many cutaneous disorders are associated with acquired immunodeficiency syndrome. We prospectively evaluated eighteen patients with acquired immunodeficiency syndrome and twelve patients with the immunodeficiency syndrome-related complex for dermatologic disorders. A high prevalence of seborrheic dermatitis was found in patients with acquired immunodeficiency syndrome--83%, in comparison with 1% to 3% of historic control subjects. Patients with the related complex also had an increased incidence of 42%. Seborrheic dermatitis in this population was often more explosive, inflammatory, and severe than is usually seen in otherwise healthy patients. Severity of seborrheic dermatitis correlated with a poor overall prognosis in our patients. Additionally, seborrheic dermatitis may be one of the most common cutaneous manifestations of acquired immunodeficiency syndrome.

Literature for parents of children with cerebral palsy.

Educational literature on cerebral palsy, designed for parents' reference, was assessed by three reviewers for content and audience appeal. Of the 88 publications received, 47 were not pertinent to the topic and 11 were useful only for reading lists, bibliographies, etc. Of the other 30 publications, 18 were deemed not useful and many of these were inaccurate and misleading. Five publications were broadly useful and a further seven were useful in part or in specific situations.