Sequentially evolved bilateral epidural haematomas.

Sequentially evolved bilateral epidural haematomas, where the second haematoma evolves after surgical removal of the first haematoma, are rarely reported. We report two cases of this entity. One patient was involved in a road traffic accident and the other was suffering from a head injury after an assault. CT scans showed that both patients had an unilateral epidural haematoma with a thin presumably epidural haemorrhage on the opposite side. Both patients were operated for their epidural haematomas, but did not improve after surgical treatment, and postoperative CT scans revealed evolving of an epidural haematoma on the opposite side. After evacuation of the second epidural haematoma both patients recovered quickly. Sequentially evolved bilateral epidural haematomas are rare, but must be considered in the postoperative intensive care treatment in patients with epidural haematomas. Both cases emphasize the need for intensive care monitoring after an operation for an epidural haematoma and the need for CT scans if the patient does not improve quickly after removal of the haematoma. This is especially important if a small contralateral haematoma is seen on the initial CT scan.

Sinusitis and ischemic stroke.

Acute sinusitis is a prevalent and generally uncomplicated infection that is normally resolved by medical therapy. However, severe neurological complications are known, and comprise of cerebral abscess, cavernous sinus thrombosis, meningitis, and epidural or subdural empyema. We report a case about a 10-year-old girl with a severe acute pansinusitis and ischemic stroke in the right lentiform nucleus and the anterior part of the right internal capsule. Possible explanations for this rare combination are discussed.

Social contingency detection and infant development.

The developmental origins and determinants of social contingency detection are discussed. Based on recent research, the author proposes that the origins of social contingency detection correspond to the early propensity developing in the first 6 months of life to differentiate between what pertains to the self (i.e., one's own body) and what pertains to others. Furthermore, from the second month of life, what infants appear to gain from contingency detection while interacting with others is a sense of shared experience or intersubjectivity. Research suggests that although the development of intersubjectivity is a central feature of infant behavior and development, the meaning of contingency detection, hence the source of intersubjectivity, changes radically between birth and 18 months of age. In general, it is proposed that the origins and determinants of social contingency detection must be construed in relation to (1) the developing sense of self in infancy, (2) the infant's developing sense of reciprocity with others, and (3) the infant's developing sense of participation with others. The author concludes by proposing a relevant map of changing social stances adopted by infants in the course of early development.

Antiepileptic drug utilization: a Danish prescription database analysis.

OBJECTIVES: The purpose of the study was to use prescription data from a Danish database to analyse and evaluate antiepileptic drug (AED) utilization, and compare with other prevalence studies. METHODS: A Danish research database covering outpatient prescription data from a population of 471,873 persons was used. Prescription records on all patients prescribed AEDs during 1998 were retrieved. A cohort was extracted from the group of AED users. RESULTS: We identified 5426 AED users. A total of 3756 of the 5426 AED users were included in our cohort. Of the subjects in the cohort 74% were on monotherapy, 19% used two AEDs and only 7% used three or more AEDs. The eight most frequent regimens were all monotherapy: carbamazepine, oxcarbazepine, phenobarbital, valproic acid, lamotrigine, clonazepam, phenytoin and primidon in that order. The estimated crude 1-year prevalence of AED use was 0.77% for women and 0.83% for men (P<0.001), and it increased with age for both genders. CONCLUSIONS: The prescription pattern reported here is in accordance with the general guidelines for the treatment of epilepsy in Denmark, except for a surprisingly extensive use of phenobarbital. With specific reservations the figures appear to be reasonable estimates of the prevalence of epilepsy.

Effects of alterations in arterial CO2 tension on cerebral blood flow during acute intracranial hypertension in rats.

Cerebrovascular reactivity to CO2 in clinical and experimental studies has been found to be impaired during increased intracranial pressure (ICP). However, from previous study results it has not been possible to estimate whether the impairment was caused by elevated ICP, or caused by decreased cerebral perfusion pressure (CPP). The current study was carried out in a group of unmanipulated control rats and in six investigation groups of six rats each: two groups with elevated ICP (30 and 50 mm Hg) and spontaneous arterial blood pressure (MABP), two groups with spontaneous ICP and arterial hypotension (77 and 64 mm Hg), and two groups with elevated ICP (30 and 50 mm Hg) and arterial hypertension (124 mm Hg). Intracranial hypertension was induced by continuous infusion of lactated Ringer's solution into the cisterna magna, arterial hypotension by controlled bleeding, and arterial hypertension by continuous administration of norepinephrine intravenously. Cerebral blood flow (CBF) was measured repetitively by the intraarterial 133Xe method at different levels of arterial PCO2. In each individual animal, CO2 reactivity was calculated from an exponential regression line obtained from the corresponding CBF/PaCO2 values. By plotting each individual value of CO2 reactivity against the corresponding CPP value from the seven investigation groups, CPP was significantly and directly related to CO2 reactivity of CBF (P < .001). No correlation was found by plotting CO2 reactivity values against the corresponding MABP values or the corresponding ICP values. Thus, the results show that CO2 reactivity is at least partially determined by CPP and that the impaired CO2 reactivity observed at intracranial hypertension and arterial hypotension may be caused by reduced CPP.

Emerging sensitivity to the timing and structure of protoconversation in early infancy.

Thirty-six 2-, 4-, and 6-month-old infants were videotaped while interacting with a female adult stranger engaging in either organized or disorganized 1-min peekaboo games. Two-month-old infants gazed and smiled equally at the stranger, regardless of the relative organization of the peekaboo game. In contrast, 4- and 6-month-old infants smiled significantly more and gazed significantly less in the organized peekaboo condition than in the disorganized peekaboo condition. These results suggest that from a diffuse sensitivity to the presence of a social partner, infants by 4 months develop a new sensitivity to the narrative envelope of protoconversation, in particular the timing and the structure of social exchanges scaffolded by adults. These observations are interpreted as evidence of developing social expectations in the first 6 months of life. This early development is viewed as announcing and preparing the communicative competence that blossoms by the end of the 1st year.

Self-perception and action in infancy.

By 2-3 months, infants engage in exploration of their own body as it moves and acts in the environment. They babble and touch their own body, attracted and actively involved in investigating the rich intermodal redundancies, temporal contingencies, and spatial congruence of self-perception. Recent research is presented, which investigates the spatial and temporal determinants of self-perception and action infancy. This research shows that, in the course of the first weeks of life, infants develop an ability to detect intermodal invariants and regularities in their sensorimotor experience, which specify themselves as separate entities agent in the environment. Recent observations on the detection of intermodal invariants regarding self-produced leg movements and auditory feedback of sucking by young infants are reported. These observations demonstrate that, early in development and long before mirror self-recognition, infants develop a perceptual ability to specify themselves. It is tentatively proposed that young infants' propensity to engage in self-perception and systematic exploration of the perceptual consequences of their own action plays an important role in the intermodal calibration of the body and is probably at the origin of an early sense of self: the ecological self.

Dynamic mental representation in infancy.

Recent research indicates that 4- to 8-month-old infants can track and anticipate the final orientation of an object following different invisible spatial transformations (Rochat, P., Hespos, S.J. (1996). Cognitive Development, 11, 3-17). Six experiments were designed to specify further the nature and development of early expectation for a set of dynamic events. A violation of expectation method was used to assess infants' reactions to probable and improbable outcomes of an objects' orientation following an invisible transformation. The availability of orientation cues, the path of motion, and the amount of invisible spatial transformation was systematically varied. The studies indicate that infants as young as 4 months of age detect orientation-specific cues for objects undergoing invisible spatial transformations. Developmental differences in this ability between 4 and 6 months of age lend insight to the nature and limitations of this early representational ability. These findings provide evidence for dynamic mental representation in infancy.

Enhanced sucking engagement by preterm infants during intermittent gavage feedings.

Non-nutritive sucking (NNS) activities were recorded in preterm infants born at gestational age 32 weeks or less during nasogastric feedings. Six infants on intermittent nasogastric feeding schedules were tested with a pacifier in their mouth for three 5-minute periods (before, during, and after gavage feeding). Analysis of the recordings revealed that NNS activities increased markedly during the intermittent nasogastric feeding schedule. The overall proportions of sucking engagement, the mean duration of sucking burst, the mean number of sucks per burst, and the mean duration of individual sucks within a burst increased markedly during gavage feeding compared with both pre-test and post-test periods. NNS by a group of five infants on continuous nasogastric feedings was similar to the pre-test and post-test of the infants on the intermittent nasogastric feeding schedule. These results indicate that in the context of intermittent nasogastric feedings, NNS engagement in tube-fed infants depends on stomach cues and/or temperature changes associated with tube feedings.

An account of the systematic error in judging what is reachable.

An account of the postural determinants of perceived reachability is proposed to explain systematic overestimations of the distance at which an object is perceived to be reachable. In this account, these errors are due to a mapping of the limits of prehensile space onto a person's perceived region of maximum stretchability, in the context of a whole-body engagement. In support of this account, 6 experiments on the judged reachability of both static and dynamic objects are reported. We tentatively conclude that the mental imagery of action is grounded and calibrated in reference to multiple skeletal degrees of behavioral freedom. Accordingly, this calibration is a source of systematic error in reachability judgments.

Perceptual strategies in the estimation of physical quantities by orangutans (Pongo pygmaeus).

The perceptual strategies used by 4 orangutans (2 subadults, 2 adults) when choosing the larger of 2 volumes in a Piagetian conservation task were investigated. Three possible perceptual strategies were investigated: (a) direct perceptual estimation of the container's content independent of its shape, (b) use of the spatial and temporal cues provided by the pouring of liquid from one container to another, and (c) ability to initially identify the larger volume and track it across transformations disregarding misleading perceptual cues. Results indicated that the direct perceptual estimation strategy was the best candidate to explain the orangutan's systematic choice of the larger of 2 quantities.

Liquid conservation in orangutans (Pongo pygmaeus) and humans (Homo sapiens): individual differences and perceptual strategies.

Four orangutans (1 juvenile, 2 subadults, and 1 adult) and ten 6-8-year-old children were tested in 4 liquid conservation tasks of increasing levels of difficulty. Task difficulty depended on the type of transformation (continuous vs. discontinuous quantities) and the relative contrast between the shapes of the containers. Results indicate that orangutans did not display conservation in the strict sense; instead they showed "partial" conservation (intermediate reactions according to J. Piaget & B. Inhelder, 1941). In contrast, some of the children provided evidence of conservation in all 4 tasks, showing "true" or logically necessary conservation in the original sense proposed by J. Piaget and B. Inhelder (1941). Although orangutans did not show conservation in the strict sense, as J. Piaget (1955) and others have generally agreed it should be defined, orangutans behaved as individual and creative problem solvers, adopting different perceptual strategies depending on the task.

Perceived reachability for self and for others by 3- to 5-year-old children and adults.

Ability to perceive the distance at which an object is within reach was assessed in 3-, 4-, and 5-year-old children and adults. In different situations, subjects had to judge whether an object placed in the vertical or horizontal plane was reachable for themselves or for someone else (the experimenter). Adults as well as children differentiated between the limits of their own prehensile space and those of another person. At all ages, children tend to attribute systematically more reachability to the adult experimenter. Furthermore, both children and adults systematically underestimate reachability for others in a horizontal presentation of the object. For all age groups, judgments of reachability for self are bodily scaled and based on perceived degrees of behavioral freedom for self and for others. From 3 years of age, children are shown to resemble adults in their ability to perceive what objects afford for action, either for self or for others. These results are interpreted as further evidence of early allocentrism (i.e., spatial decentration and perspective taking) in the context of a practical task.

Multimodal perception in the control of infant reaching.

Six-month-old infants were presented with sounding objects under 3 conditions of illumination: in full vision, in the dark with target location specified by a glowing and sounding object, and in the dark with location specified by sound alone. Reaching behavior was videotaped with an infrared camera, and hand movement was measured by infrared-emitting diodes on the hand that were tracked by a motion analysis system. No differences were found in reaching behavior for objects in the light and glowing objects in the dark. Reaches for sounding objects in the dark had higher speeds, shorter durations, and more errors compared to the other 2 conditions. These findings indicate that vision of the hand did not appear to affect infants' reaching in this situation, whereas vision of the target did.

Self-sitting and reaching in 5- to 8-month-old infants: the impact of posture and its development on early eye-hand coordination.

The relation between progress in the control of posture (i.e., the achievement of self-sitting posture) and the developmental transition from two-handed to one-handed engagement in infant reaching was investigated. Two groups of 5- to 8-month-old infants, who were either able or yet unable to sit on their own, were videotaped while they reached for objects in four different posture conditions that provided varying amounts of body support. Videotapes of infant reaches were microanalyzed to determine the relative engagement of both hands during reaches. Results demonstrate the interaction between postural development and the morphology of infant reaching. Nonsitting infants displayed symmetrical and synergistic engagement of both arms and hands while reaching in all but the seated posture condition. Sitting infants, by contrast, showed asymmetrical and lateralized (one-handed) reaches in all posture conditions. Results also show that, aside from posture, the perceived spatial arrangement of the object display is a determinant of infant reaching. Combined, these results are discussed as evidence for the interaction between postural and perceptual development in the control of early eye-hand coordination.

Object representation guides infants' reaching in the dark.

Infants were presented with two sounding objects of different sizes in light and dark, in which sound cued the object's identity. Reaching behavior was assessed to determine if object size influenced preparation for grasping the object. In both light and dark, infants aligned their hands when contacting the large object compared with the small object, which resulted in a reach with both hands extended for the large object and reach with one hand more extended for the small object. Infants contacted the large object more frequently on the bottom and sides rather than the top, where the sound source was located. Reaching in the dark by 6 1/2-month-olds is not merely directed toward a sound source but rather shows preparation in relation to the object's size. These findings were interpreted as evidence that mental representation of previously seen objects can guide subsequent motor action by 6 1/2-month-old infants.