Neuropsychological outcome in children with optic pathway tumours when first-line treatment is chemotherapy.

Standard treatment of optic pathways gliomas consists of radiotherapy and surgery when feasible. Owing to the toxicity of irradiation, chemotherapy has emerged as an interesting therapeutic option, especially in young children. This study describes the neuropsychological profile of 27 children (aged between 1.5 and 15.7 years) with optic pathways gliomas treated with chemotherapy as first-line treatment. Eight of them also received radiotherapy as salvage treatment. Eight had neurofibromatosis type 1 (NF1). Intellectual outcome was preserved in children treated with chemotherapy only (mean=107+/-17) compared to children also receiving radiotherapy (mean IQ=88+/-24) or children having NF1 and treated with chemotherapy (mean IQ=80+/-13). Scores for abstract reasoning, mental arithmetic, chessboard/coding, perception, judgement of line orientation were lower in children irradiated than in those treated only by chemotherapy. Children with Nf1 showed subnormal IQ scores with marked impairment of short- and long-term memory. With respect to long-term neuropsychological outcome, our study shows that a chemotherapy-first strategy can preserve the intellectual outcome of these patients either by avoiding the need of radiotherapy or by delaying its use as much as possible.

Haptic memory and handedness in 2-month-old infants.

This study examined the robustness of infant haptic memory, asymmetry between hands, and sex differences in haptic memory in infancy. A total of 96 2-month-old infants (half males, half females) were habituated haptically to an object with their right and their left hand, out of the field of view. Haptic memory was then tested under three conditions: after haptic interference, after a 30-second delay, or after no delay. The results show that haptic habituation occurred for both hands. The girls needed more time to habituate with their left hand than with their right hand, and they habituated more slowly than the boys did. Discrimination was also found in both hands and in both sexes. Haptic delayed recognition memory was only found in young boys mainly after a short delay and under certain conditions after interference. In young girls, recognition memory was found after interference only with the left hand. This result seemed to depend on the information processing speed. Thus, for memory performance, a sex difference was clearly observed. Moreover, the infants' left hand retained better information on object shape than did the right hand for both the sexes. Asymmetries in infancy are discussed in connection with the difference in brain maturation rate.

Modality-specific and amodal aspects of object perception in infancy: the case of active touch.

Three experiments investigated 4.5-month-old infants' perception of the unity and boundaries of haptically presented objects. When infants actively explored the two handles of an unseen object assembly, perception of the unity of the assembly depended on the handles' motion. Infants perceived a single, connected object if the handles moved rigidly together, and they perceived two distinct objects if the handles underwent relative vertical or horizontal motion. When infants passively explored the same object assembly undergoing the same motions, object perception appeared to be indeterminate. The findings of the active motion experiments accord with the findings of studies of visual object perception and suggest that object perception depends on amodal processes, operating on representations of either seen or felt surface motions. The findings of the passive motion experiments nevertheless suggest a difference between visual and haptic perception: for infants as for adults, haptic perception is enhanced by the active production of surface motion.

Visual-tactual and tactual-visual transfer between objects and pictures in 2-month-old infants.

Previous studies have provided evidence for transfer of perception of object shape from touch to vision, but not from vision to touch, in young infants. Previous studies also indicate that intermodal recognition can produce a preference either for a matching or for a nonmatching object. We investigated the causes of asymmetries in intermodal transfer and of conclusions: (i) Transfer from vision to touch is possible under certain conditions and is facilitated by the use of two-dimensional (2-D) visual representations rather than three-dimensional (3-D) visual objects. (ii) The direction of preferences in a transfer task depends on the degree of dissimilarity between the haptically and visually presented objects. Familiarity preferences increase with increasing difference between the object to be recognised and the familiar object. (iii) Infants are able to perceive the 3-D shape of an object both visually and haptically, and they are sensitive both to commonalities and to discrepancies between the shapes of 3-D objects and of their 2-D representations. Hierarchical levels of perceptual processing are proposed to account for these findings.

Intermodal transfer of spatial arrangement of the component parts of an object in infants aged 4-5 months.

Infants' tactual discriminative abilities and intermodal transfer were investigated in two research studies which endeavoured to answer two questions: can infants aged 4-5 months process and discriminate tactually information about different spatial arrangements of elements of an object, in the absence of visual control, and secondly, can they transfer this information from touch to vision? Two experiments were conducted involving a habituation procedure and a procedure which tests reaction to novelty. Infants were found to be able to discriminate tactually between different spatial arrangements of the three elements of an object (experiment 1), and to transfer this information to the visual mode (experiment 2). These findings constitute new data on intermodal functioning in babies.

Effects of motion and figural goodness on haptic object perception in infancy.

4-month-old infants held 2 rings, 1 in each hand, out of view. The rings moved rigidly together and were either the same (Experiment 1) or different (Experiment 2) in substance, weight, texture, and shape. After haptic habituation to a ring display, patterns of preferential looking to visibly connected vs. separated rings provided evidence that the infants perceived the rings in both experiments as parts of one connected object. This perception was no weaker when the rings differed in shape and substance, even though infants were shown (Experiment 3) to detect that difference. In the haptic mode, as in the visual mode, infants appear to perceive object unity by analyzing motion but not by analyzing figural goodness. The findings suggest that an amodal mechanism underlies object perception.

Tactual habituation and discrimination of form in infancy: a comparison with vision.

Tactual discriminative abilities out of the control of vision are studied in 5-month-old infants, and compared with their visual discriminative abilities. The relevance of a habituation/reaction to novelty procedure in the tactual modality is tested. An infant control procedure is used in both modalities on 2 independent samples of 32 infants each. Habituation and discrimination occur tactually as well as visually, the duration of holds decreasing more than the duration of looks. Accumulated holding time is 3 times longer than accumulated looking time. Analogies and discrepancies between tactual and visual habituations are discussed, and the problem of sensory dominance is raised. Such results are basic to studies on cross-modal transfer, from vision to touch as well as from touch to vision.