Excessive checking for non-anxiogenic stimuli in obsessive-compulsive disorder.

BACKGROUND: Repetitive checking in obsessive-compulsive disorder (OCD) would serve to relieve obsession-related anxiety and/or to compensate memory deficit, but experimental literature on this subject is inconsistent. The main objective is to test the influence of obsession-related anxiety and memory on repetitive checking in OCD. METHODS: Twenty-three OCD checkers, 17 OCD non-checkers and 41 controls performed a delayed-matching-to-sample task with an unrestricted checking option. Some stimuli were obsession-related in order to measure the influence of anxiety on checking. A version of the task without checking possibility was used to assess memory abilities. RESULTS: OCD checkers had similar memory performances but checked more than the other groups when presented with non-anxiogenic stimuli. Level of anxiety associated to the stimulus did not influence the number of checks. CONCLUSIONS: Increased checking in OCD checkers, being independent of memory abilities and primary obsession-related anxiety, would, therefore, be closer to an automated behaviour than a coping strategy.

A challenging task for assessment of checking behaviors in obsessive-compulsive disorder.

OBJECTIVE: The present study concerns the objective and quantitative measurement of checking activity, which represents the most frequently observed compulsions in obsessive-compulsive disorder (OCD). To address this issue, we developed an instrumental task producing repetitive checking in OCD subjects. METHOD: Fifty OCD subjects and 50 normal volunteers (NV) were administered a delayed matching-to-sample task that offered the unrestricted opportunity to verify the choice made. Response accuracy, number of verifications, and response time for choice taken to reflect the degree of uncertainty and doubt were recorded over 50 consecutive trials. RESULTS: Despite similar levels of performance, patients with OCD demonstrated a greater number of verifications and a longer response time for choice before checking than NV. Such behavioral patterns were more pronounced in OCD subjects currently experiencing checking compulsions. CONCLUSION: The present task might be of special relevance for the quantitative assessment of checking behaviors and for determining relationships with cognitive processes.

Specific cerebral networks for maintenance and response organization within working memory as evidenced by the 'double delay/double response' paradigm.

Most of the working memory (WM) tasks used in functional imaging studies are based on the principle of the delayed response in which both the storage and the response organization are present during the delay period. It is therefore difficult to isolate activation specific to the storage function from that specific to the organization of the response. To determine the specific neural networks associated with these two WM operations, we performed a functional MRI study in healthy subjects using a new paradigm, 'the double delay/double response' tasks. This paradigm isolates maintenance from response organization by dividing the delay into two separate parts, the first being dedicated to memory, while the second includes response organization. Activation within the dorsolateral prefrontal cortex (DLPFC) followed a relative hemispheric dissociation: activation related to maintenance was predominant in the right DLPFC but was only detected when the load exceeded three items. Activation related to response organization was predominant in the left DLPFC, regardless of whether this response was based on information held in WM ('memory guided') or was independent of WM ('visually-guided'). These results suggest that activation of the DLPFC, should be interpreted in terms of executive processing for both maintenance and response organization.

Executive functions and updating of the contents of working memory in unipolar depression.

BACKGROUND: Depression is characterized by cognitive impairments, including executive dysfunctions. These executive deficits could reflect impairments of more basic executive processes, such as updating, set shifting and inhibition. While shifting and inhibition impairments are often reported, studies on depression have been somewhat obscure about specific deficits of the updating process. The main goal of that study was to assess the updating process in young in-patients with depression. METHODS: We used a verbal n-back task to assess updating process. Load and mental manipulation within working memory (WM) were incremented by using three different levels of complexity (1,2,3-back). Neuropsychological tests and an attentional task (0-back) were also administered to subjects. Twenty-two individuals meeting DSM-IV criteria for Major Unipolar Depression and 22 healthy control subjects, matched on age, verbal IQ and education, were included in the study. RESULTS: Subjects with depression showed significant deficits at the n-back task compared to control subjects. They were normal in tasks assessing the short-term maintenance in WM and attention. This suggests that depressed patients exhibit impairment in the updating process. Depressed patients also showed set shifting and inhibition deficits. Only the n-back task was correlated with the number of hospitalizations and the longitudinal course of the illness. CONCLUSIONS: Our results suggest that young depressed in-patients have widespread executive dysfunctions, including updating, shifting and inhibition processes. We also found a correlation between a longitudinal measure of depression severity and an updating task performance. We suggest that using multiple executive tasks gives the opportunity to distinguish the specific influence of various executive processes on clinical dimensions in depression.

Motivation, reward, and Parkinson's disease: influence of dopatherapy.

"Orbitofrontal" and "cingulate" striatofrontal loops and the mesolimbic dopaminergic system that modulates their function have been implicated in motivation and sensitivity to reinforcement in animals. Parkinson's disease (PD) provides a model to assess their implications in humans. The aims of the study were to investigate motivation and sensitivity to reinforcement in non-demented and -depressed PD patients and to evaluate the influence of dopaminergic therapy by comparing patients in "on" (with L-Dopa) and "off" (without L-Dopa) states. Twenty-three PD patients were compared, in both the "on" and "off" states, to 28 controls, using: (1) an Apathy Scale; (2) Stimulus-Reward Learning, Reversal, and Extinction tasks; and (3) a Gambling task. PD patients were found: (1) mildly apathetic; (2) impaired on Stimulus-Reward Learning and Reversal, but not on Extinction; and (3) able to progress in the Gambling task during the first, but not the second assessment. There was no significant correlation between these various deficits. L-Dopa treatment clearly improved motivation, but had more limited and contrasting effects on other variables, decreasing the number of omission errors in Reversal, but increasing the number of perseveration errors in Extinction. These results suggest: (1) an implication of striatofrontal loops in human motivation and explicit and implicit sensitivity to reinforcement; (2) a positive influence of L-Dopa treatment on the subjective evaluation of motivation, but contrasting effects on reward sensitivity.

The neural system that bridges reward and cognition in humans: an fMRI study.

We test the hypothesis that motivational and cognitive processes are linked by a specific neural system to reach maximal efficiency. We studied six normal subjects performing a working memory paradigm (n-back tasks) associated with different levels of monetary reward during an fMRI session. The study showed specific brain activation in relation with changes in both the cognitive loading and the reward associated with task performance. First, the working memory tasks activated a network including the dorsolateral prefrontal cortex [Brodmann area (BA) 9/46] and, in addition, in the lateral frontopolar areas (BA 10), but only in the more demanding condition (3-back task). This result suggests that lateral prefrontal areas are organized in a caudo-rostral continuum in relation with the increase in executive requirement. Second, reward induces an increased activation in the areas already activated by working memory processing and in a supplementary region, the medial frontal pole (BA 10), regardless of the level of cognitive processing. It is postulated that the latter region plays a specific role in monitoring the reward value of ongoing cognitive processes. Third, we detected areas where the signal decreases (ventral-BA 11/47 and subgenual prefrontal cortices) in relation with both the increase of cognitive demand and the reward. The deactivation may represent an emotional gating aimed at inhibiting adverse emotional signals to maximize the level of performance. Taken together, these results suggest a balance between increasing activity in cortical cognitive areas and decreasing activity in the limbic and paralimbic structures during ongoing higher cognitive processing.

Is the HM story only a "remote memory"? Some facts about hippocampus and memory in humans.

In this review, we argue that a number of current data support the notion that the hippocampal formations play an important role in episodic memory in humans. We will focus on data gathered from three topics within this field: (1) the neuropsychological study of memory in degenerative diseases, which provides striking dissociations of processes, as a function of the location of cerebral lesions and of their functional consequences; (2) the description of patients' memory difficulties after unilateral medial temporal lobectomy. Given the visuo-verbal dissociation, we may anticipate that the study of the effects of such lesions may help in the understanding of the role of the hippocampus in memory, in terms of: (i) the stage of memory processing where the hippocampus is really involved (encoding, consolidation and/or retrieval); (ii) the specificity of the impairments as a function of the nature (verbal vs. visuo-spatial) of the to-be-remembered material; (3) recent evidence from imaging studies: (i) the morphological approach, which provides interesting information with the study of correlations between the volumes of diverse cerebral regions-particularly the volume of the hippocampus-and episodic memory performance and other cognitive measures; (ii) metabolic studies, using PET scan, which were first designed for correlational analyses between performance in episodic memory tasks and glucose utilization at rest in diverse regions of interest, such as the hippocampal formations; (iii) activation studies with PET and functional MRI, which are actually more straightforward, since they allow correlations between the metabolism in regions of interest and performance on line (e.g. during encoding or retrieval of information). In our view, inasmuch as such different approaches-degenerative diseases, lesions or imagery-provide convergent information, they give renewed weight to the notion according to which the hippocampal formations are critically concerned in episodic memory processes.

The role of dorsolateral prefrontal cortex in the preparation of forthcoming actions: an fMRI study.

The dorsolateral prefrontal cortex (DLPFC) plays a key role in working memory (WM). Yet its precise contribution (the storage, manipulation and/or utilization of information for the forthcoming response) remains to be determined. To test the hypothesis that the DLPFC is more involved in the preparation of actions than in the maintenance of information in short-term memory (STM), we undertook a functional magnetic resonance imaging investigation in normal subjects performing two delayed response tasks (matching and reproduction tasks) in a visuospatial task sequence (presentation, delay, response). In the two tasks, the presentation and delay phases were similar, but the expected response was different: in the matching task, subjects had to indicate whether a visuospatial sequence matched the sequence presented before the delay period; in the reproduction task, subjects had to reproduce the sequence and, therefore, to mentally organize their response during the delay. Using a fMRI paradigm focusing on the delay period, we observed a significant DLPFC activation when subjects were required to mentally prepare a sequential action based on the information stored in STM. When subjects had only to maintain a visuospatial stimulus in STM, no DLPFC activation was found. These results suggest that a parietal-premotor network is sufficient to store visuospatial information in STM whereas the DLPFC is involved when it is necessary to mentally prepare a forthcoming sequential action based on the information stored in STM.

[Ambulatory pediatric surgery]. / Ambulante Kinderchirurgie.

The authors refer about their experience in ambulatory pediatric surgery performed in pediatric clinics or in their own practice. Indications are listed, conditions, advantages and disadvantages are discussed. 562 operations were completed from February 1991 to January 1992, 181 (32%) under practice conditions with an experienced anesthesiologist. No complications had to be reported, and no patient was hospitalized due to surgical or anesthetic complications. But indications for ambulatory surgery have to be strictly noted, and only children in excellent health should be anesthesized. The decision about operability has to be made by the anesthesiologist in charge.

Operative treatment of solitary bone cysts with tricalcium phosphate ceramic. A 1 to 7 year follow-up.

From 1984 to 1990 we treated 18 patients aged 5 to 15 1/2 years with solitary bone cysts of the humerus, the femur and the calcaneus. To fill the defect, tricalcium phosphate (TCP) instead of bone grafting was used. The clinical and radiological long-term results up to seven years postoperatively are reported. In 16 patients TCP was well incorporated without any adverse reaction to the synthetic material. Two patients with a recurrence of the bone cyst were successfully reoperated. We conclude that ceramics are a cheap and easy available substitute for bone grafts in the treatment of solitary bone cysts.

Cranioplasty for acquired skull defects in children--a comparison between autologous material and methylmethacrylate 1974-1990.

The authors report on their experiences with 21 patients with skull defects which were closed by polymethylmethacrylated plates (PMMA) from 1974 to 1990 at the University Children's Hospital in Zurich and the "Gemeinschaftspraxis fuer Kinderchirurgie". The results were compared with 15 cases treated by autologous grafts. Because of false indication, one case of PMMA-plasty led to an infected fistula. Otherwise no adverse reactions were noted. Three of the 15 cases with autologous grafts showed resorption. Polymethylmethacrylate is an excellent agent for skull reconstruction. The simple procedure, shorter OP time, and lack of pain or disfigurement due to a donor site signify a great advantage to this method.

[Intra-articular finger fractures in children]. / Intraartikuläre Fingerfrakturen im Kindesalter.

From 1982 to 1984 140 patients with fractures of the fingers were admitted to the department of surgery of the University Children's Hospital. Only 28 patients (21.5%) suffered from intraarticular fractures. Three 3/12 years later, 10 patients (35.7%) presented functional trouble or suffered from pain. Only 2 of the 15 conservatively treated patients had trouble. On the other hand, 8 children out of the 13 operatively treated patients presented an unsatisfactory result. Localisation, type of fracture and kind of treatment are analysed. We prefer as a rule conservative treatment excepting fractures of type Salter III and IV, osseous ruptures of the ulnar collateral ligament of the thumb and dislocated fractures. We suggest splinting with 0.6 mm K-wires.

[Congenital hydrocephalus--preoperative assessment and intraoperative findings in congenital hydrocephalus]. / Der konnatale Hydrozephalus--Präoperative Abklärungen und intraoperative Befunde beim konnatalen Hydrozephalus.

54 children already presented in Part 1 were analysed with regard to their preoperative aetiopathological findings and evolution of different parameters until surgery. Our interest was focussed on possible correlations between brain malformation and head circumference as well as both ICP and neurological evolution. We examined the presence of infectious diseases in the preoperative period and checked on the advantage of a perioperative antibiotic therapy. We could not find any correlation between the aetiopathological findings in X-ray investigation and head circumference or ICP or preoperative neurological findings. Perioperative antibiotic therapy does not seem to be an additional safety factor.

Deleterious consequences of gastroesophageal reflux in cleft larynx surgery.

Our series of 17 children with laryngotracheal clefts is reported. In three of four cases with a complicated postoperative course, gastroesophageal reflux (GER) has been found. Three breakdowns of the surgical repair opposed to be due to GER. Only one child with a cleft type III died, although a mortality rate of 93% is reported in the literature. GER has to be excluded before tracheoesophageal cleft surgery is undertaken.

[Bone replacement using beta-tricalcium phosphate--results of experimental studies and initial clinical case examples]. / Knochenersatzplastiken mit Beta-Tricalciumphosphat--Resultate experimenteller Studien und erste klinische Fallbeispiele.

Beta-Tricalcium phosphate granulates (Ceros 82) implanted in femurs of the rat led to osteoconduction already one week after implantation. Compared to the problems of autologous implants, TCP presents many advantages: No operation on the donor site, no limitation of quantity, clinically negligible resorption, immediate osteoconduction. The results on femoral defects of 26 rats filled up by beta-TCP and our first clinical experiences on juvenile bone cysts are presented.

[In vitro studies on Geliperm Dry as a vehicle for antibiotics and antiseptics in local burn therapy]. / In vitro-Versuche mit Geliperm Dry als Träger für Antibiotika und Antiseptika in der lokalen Verbrennungstherapie.

Geliperm is a synthetic skin substitute, consisting of polysaccharid-polyacrylic plates. It is available as a soaked or a dried form (Geliperm dry). Geliperm dry can be soaked in antibiotic or antiseptic solutions. The in vitro inhibition of bacterial growth has been measured. The optimal concentrations have been evaluated. Geliperm dry soaked in antibiotic or antiseptic solutions can be used in the treatment of burns, but does not replace early excision of burned tissue or infected necrosis.