Sensorized assessment of bilateral hand movements in patients with stroke driven by rhythmic auditory or visual-auditory stimulation.

There is a growing body of literature about the efficacy in neurorehabilitation of the devices providing rhythmic auditory stimulations or visual-auditory stimulations, such as videogames, for guiding the patients' movements. Despite being presented as tools able to motivate patients, their efficacy was not been proven yet, probably due to the limited knowledge about the factors influencing the capability of patients to move the upper limbs following an external stimulus. In this study, we used a marker less system based on two infrared sensors to assess the kinematics of up and down in-phase and anti-phase bilateral hand oscillations synchronized or not with an external stimulus. A group of stroke survivors, one of age-matched healthy subjects and one of young healthy subjects were tested in three conditions: no stimulus, auditory stimulus, and video-auditory stimulus. Our results showed significant negative effects of visual-auditory stimulus in the frequency of movements (p = 0.001), and of auditory stimulus in their fluidity (p = 0.013). These results are conceivably related to the attentional overload required during the execution of bilateral movements driven by an external stimulus. However, a positive effect of external stimulus was found in increasing the range of movements of the less functional hand in all subjects (p = 0.023). These findings highlight as the type of stimulus may play a crucial role in the patient's performance with respect to movements that are not-externally driven.

Reading skills in children with mild to borderline intellectual disability: a cross-sectional study on second to eighth graders.

BACKGROUND: Students with intellectual disabilities (IDs) have various learning difficulties and are at risk for school failure. Large inter-individual differences are described for reading, but it is unclear how these vary as a function of grade. The aim of this study was to examine various reading fluency, accuracy and comprehension parameters in second-to-eighth-grade Italian children with either borderline intellectual functioning (BIF) or mild ID (MID). METHODS: We examined 106 children with BIF (67 M and 39 F) and 168 children with MID (107 M and 61 F). The children were in the second to eighth grade and were comparable for chronological age (7 to 14 years). They were administered a battery of tests that assessed fluency and accuracy of word, pseudo-word and text reading, as well as text comprehension. Standardised scores allowed us to compare the performance of the two groups with normative values. RESULTS: Children with ID obtained generally low scores compared with normative values. Those with MID had greater difficulty than those with BIF. Furthermore, difficulty was greater for speed than for accuracy measures and for words than for pseudo-words. Difficulty (particularly in the case of reading speed) tended to be pronounced at later grades. Marked individual differences were present independently of MID-BIF subgrouping, as well as stimulus category and reading parameter. CONCLUSIONS: As a group, children with ID showed difficulty in reading acquisition; the effect was greater for children with more severe ID, but large individual differences were observed in children with both BIF and MID. Relatively spared pseudo-word reading skills indicate efficient use of the grapheme-to-phoneme conversion routine. This processing mode may prove more ineffective at higher levels of schooling when even in regular orthographies such as Italian typically developing children rely on lexical activation.

Italian normative data for a stroke specific cognitive screening tool: the Oxford Cognitive Screen (OCS).

Cognitive deficits occur in most stroke patients and cognitive impairment is an important predictor of adverse long term outcome. However, current screening measures, such as the Mini Mental State Examination or the Montreal Cognitive Assessment, do not provide information tuned for evaluating the impact of cognitive impairment in the early phase after stroke. The Oxford Cognitive Screen (OCS) represents an important new development in this regard. The OCS is now available for assessment of Italian individuals and the aim of this study is to standardize the OCS on a large sample of healthy Italian participants stratified for age, gender and education level. Results confirmed the influence of these factors in several of the OCS tasks. Age-, education- and gender-adjusted norms are provided for the ten sub-tests of the test. The availability of normative data represents an important prerequite for the reliable use of OCS with stroke patients.

Italian standardization of the Apples Cancellation Test.

Hemispatial neglect due to right parieto-temporo-frontal lesions has a negative impact on the success of rehabilitation, resulting in poor functional gain. Recent research has shown that different types of neglect can impact in a different way on rehabilitation outcomes. The availability of a sensitive test, useful for distinguishing egocentric and allocentric forms of neglect, may be clinically important as all current clinical instruments fail to distinguish between these forms of disturbance, yet they differentially predict outcome. The Apples Test is a new instrument useful to evaluate both egocentric and allocentric forms of neglect. In order to establish Italian norms for this diagnostic instrument the test was administered to a sample of 412 healthy people of both genders (201 M and 211 F), aged from 20 to 80 years enrolled from 14 different rehabilitation centers in Italy. Based on the data, we established pathological performance cut-offs for the accuracy score (total omission errors), the asymmetry score for egocentric neglect (omission error difference), the asymmetry score for allocentric neglect (commission error difference) and execution time. The usefulness of the Apples Test for diagnostic purposes is illustrated by presenting three patients with different forms of neglect (egocentric, allocentric and mixed neglect).

Selective and integrated rehabilitation programs for disturbances of visual/spatial attention and executive function after brain damage: a neuropsychological evidence-based review.

The present evidence-based review systematically examines the literature on the neuropsychological rehabilitation of attentional and executive dysfunctions in patients with acquired brain lesions. Four areas are considered: 1) neuropsychological rehabilitation of attentional disorders; 2) neuropsychological rehabilitation of neglect disorders; 3) neuropsychological rehabilitation of dysexecutive disorders and 4) rehabilitation trainings for patients with mild traumatic brain injury (TBI). In each area, search and selection of papers were performed on several databases and integrated by crosschecking references from relevant and recent reviews. The literature up to 2007 was examined (in some areas the search was limited from 2000 to 2007). Class of evidence for each selected study was evaluated according to the SPREAD (2010) criteria. Based on this analysis, recommendations on the effectiveness of rehabilitation trainings are proposed separately for each rehabilitation method in each of the four areas considered. Information on follow-up data and impact on activities of daily living is provided whenever available.

Abnormal motor preparation in severe traumatic brain injury with good recovery.

Movement-related cortical potentials (MRCPs) were examined in seven patients with severe traumatic brain injury (TBI) and 12 matched control subjects. All patients had clinically established good recovery by the time of testing. Flexion movements of the index finger of the left or right hand were recorded in two (alternating and repetitive) self-paced conditions and in one externally triggered condition. In control subjects, the bereitschaftspotential (BP) component of MRCP was detected approximately 2000 msec prior to movement onset in the self-paced conditions and was larger and earlier in the alternating compared to the repetitive condition. The BP component was absent in the externally triggered condition. In TBI patients, the BP was greatly reduced and no difference between the alternating-repetitive conditions was detected; in contrast, only small differences were present in the controls for the negative slope (NS) and MP components and no difference for the reafferent positivity (RAP) component. A dipole analysis indicated the supplementary motor area and the premotor area as the likely generators of BP and NS' components, respectively. Gradientrecalled echo magnetic resonance imaging allowed the detection of a number of small hypointense lesions primarily located in the frontal lobes, as in diffuse axonal injury. This pattern of results indicates a selective deficit in motor preparation and a relatively spared pattern of activation during and following movement in these patients. Imaging data appear generally consistent with the pattern of MRCPs observed in the patient group. Implications of these results for the problem of slowness in TBI patients are discussed.

Large errors in the perception of vertically are generated by luminance borders (integrated across space) not by subjective borders.

The rod-and-frame illusion shows large errors in the judgment of visual vertical in the dark if the frame is large and there are no other visible cues (Witkin and Asch, 1948 Journal of Experimental Psychology 38 762-782). Three experiments were performed to investigate other characteristics of the frame critical for generating these large errors. In the first experiment, the illusion produced by an 11 degrees tilted frame made by luminance borders (standard condition) was considerably larger than that produced by a subjective-contour frame. In the second experiment, with a 33 degrees frame tilt, the illusion was in the direction of frame tilt with a luminance-border frame but in the opposite direction in the subjective-contour condition. In the third experiment, to contrast the role of local and global orientation, the sides of the frame were made of short separate luminous segments. The segments could be oriented in the same direction as the frame sides, in the opposite direction, or could be vertical. The orientation of the global frame dominated the illusion while local orientation produced much smaller effects. Overall, to generate a large rod-and-frame illusion in the dark, the tilted frame must have luminance, not subjective, contours. Luminance borders do not need to be continuous: a frame made of sparse segments is also effective. The mechanism responsible for the large orientation illusion is driven by integrators of orientation across large areas, not by figural operators extracting shape orientation in the absence of oriented contours.

Influence of the radial and vertical dimensions on lateral neglect.

The influence of radial (near-far) and vertical (upper-lower) dimensions on lateral visuo-spatial neglect was studied using two horizontal line-bisection tasks (one motor and one perceptual). A group of 15 patients with neglect and a group of 14 right-brain damaged patients without neglect were examined. This latter group was used to define the range of variability in line-bisection performance that was independent of neglect. For the radial dimension, some neglect patients showed greater errors in far space than in near space (for both stimuli presented in the upper and lower space). Fewer patients showed the opposite pattern (i.e., greater errors for near-space stimuli). These near-far asymmetries were present for both the motor and perceptual conditions and showed a good degree of intra-individual consistency. This finding contradicts the hypothesis that the motor component is critical for yielding such asymmetry. For the vertical dimension, the results indicated that neglect patients make more bisection errors for lower-space stimuli than for upper-space stimuli. This vertical asymmetry was nearly always confined to stimuli in near space. Asymmetries along the vertical dimension were present for both perceptual and motor conditions, although intra-individual consistency was low. When perceptual and motor conditions were directly compared, several neglect patients showed greater errors in the perceptual than in the motor task.

Patterns of attentional impairment following closed head injury: a collaborative European study.

A comprehensive assessment of both selective (focused attention, divided attention) and intensive (alertness and vigilance) attentional processes was performed on 106 patients with closed head injury using a computerised battery for the evaluation of attention. All patients were tested at least five months after their accident. A high percentage of patients were pathological in tests mapping the selective components of attention while only a minority were impaired on tests mapping the intensive components of attention. Three different subgroups of patients with consistent performance patterns were evidenced. The psychometric characteristics of the battery and its possible clinical usefulness are discussed.

Eye movement patterns in linguistic and non-linguistic tasks in developmental surface dyslexia.

Ten subjects who could be reliably assessed as surface dyslexics were selected on the basis of a large test battery. Eye movements in non-linguistic and linguistic tasks were studied in these subjects. Stability of fixation on a stationary stimulus was examined. Performance of dyslexics was no different from that of an age-matched control group. Similarly, no difference was observed between the two groups when they were requested to saccade to a rightward or leftward target. On the other hand, while reading short passages, dyslexics showed an altered pattern of eye movements with more frequent and smaller rightward saccades as well as longer fixation times. The reading pattern was analysed by eye tracking. Numerous fixations were used to read a single word in a fragmented way. Longer words showed a higher number of fixations. Overall, it was concluded that surface dyslexia is not associated with oculo-motor dysfunction and the study of eye movements in reading reveals the processing through orthography-to-phonology conversion characteristic of surface dyslexia. The importance is stressed of examining selected groups of subjects in the psychophysiological study of dyslexia.

Hierarchical organisation in perception of orientation.

According to Rock [1990, in The Legacy of Solomon Asch (Hillsdale, NJ: Lawrence Erlbaum Associates)], hierarchical organisation of perception describes cases in which the orientation of an object is affected by the immediately surrounding elements in the visual field. Various experiments were performed to study the hierarchical organisation of orientation perception. In most of them the rod-and-frame-illusion (RFI: change of the apparent vertical measured on a central rod surrounded by a tilted frame) was measured in the presence/absence of a second inner frame. The first three experiments showed that, when the inner frame is vertical, the direction and size of the illusion are consistent with expectancies based on the hierarchical organisation hypothesis. An analysis of published and unpublished data collected on a large number of subjects showed that orientational hierarchical effects are independent from the absolute size of the RFI. In experiments 4 to 7 we examined the perceptual conditions of the inner stimulus (enclosure, orientation, and presence of luminance borders) critical for obtaining a hierarchical organisation effect. Although an inner vertical square was effective in reducing the illusion (experiment 3), an inner circle enclosing the rod was ineffective (experiment 4). This indicates that definite orientation is necessary to modulate the illusion. However, orientational information provided by a vertical or horizontal rectangle presented near the rod, but not enclosing it, did not modulate the RFI (experiment 5). This suggests that the presence of a figure with oriented contours enclosing the rod is critical. In experiments 6 and 7 we studied whether the presence of luminance borders is important or whether the inner upright square might be effective also if made of subjective contours. When the subjective contour figure was salient and the observers perceived it clearly, its effectiveness in modulating the RFI was comparable to that observed with luminance borders.

Developmental surface dyslexia is not associated with deficits in the transient visual system.

Deficits of the transient visual system have been reported in unselected groups of dyslexics. The aim of this study was to examine whether this finding holds when subjects with a specific type of developmental reading disorder (surface dyslexia) are considered. Ten Italian children were examined. They all presented the characteristic markers of surface dyslexia: slow and laborious reading with errors in tasks which cannot be solved with a grapheme-phoneme conversion (i.e., homophones). Contrast sensitivity thresholds to phase-reversal gratings were within normal limits for most subjects both for stimuli presented centrally and in the right parafovea. This indicates that developmental surface dyslexia is not associated with a deficit in the transient system. In contrast, sensitivity to high spatial frequency stationary stimuli was reduced.

Frame-of-reference and hierarchical-organisation effects in the rod-and-frame illusion.

Two hypotheses proposed as alternatives by Rock--frame of reference and hierarchical organisation of perception--were tested in a series of experiments with the use of the rod-and-frame illusion. This illusion produces errors in the apparent vertical due to the presence of a tilted frame surrounding the test rod. The apparent vertical is shifted in the direction of the frame tilt. When an upright square was added inside the tilted frame, rod-setting errors varied according to the visual characteristics of the display. In the case of a large display presented in the dark (experiment 1), there continued to be large errors in the direction of the outer-square tilt. This finding supports the frame-of-reference hypothesis, which proposes that the orientation of all objects in the visual field is dominated by the most peripheral reference. In the case of a small display presented in a lit environment (experiments 2 and 3), the direction of errors was the opposite. This latter finding was taken to indicate that the rod was set with reference to the perceived tilt of the inner upright square. Thus, according to a hierarchical-organisation hypothesis, the orientation of an object in the visual field is influenced by objects in the immediate surroundings not by outermost reference. Overall, the results confirm the presence of two qualitatively different classes of orientational phenomena: one is concerned with the definition of egocentric coordinates and one with an object-centred visual representation.

Vertical neglect: behavioral and electrophysiological data.

Both behavioral and electrophysiological methods were used to assess altitudinal neglect. In the first experiment, 100 patients with neglect completed Albert's Barrage test. Most omissions were present in the lower left quadrant. In 16 patients, visual evoked potentials to stimuli in the four quadrants were separately recorded (Exp. 2). Latencies in the lower left quadrant were longer than those in the other quadrants. A third experiment provided electrophysiological normative data from 13 young normal subjects. Overall, the results showed that both the horizontal and vertical dimensions of space are affected in neglect patients.

Eye movement patterns in reading as a function of visual field defects and contrast sensitivity loss.

Saccadic eye movements during reading were examined as a function of the side of visual field cut and the impairment of visual contrast sensitivity Five patients with various visual field defects were compared to five age-matched controls. Patients with right visual field defect showed an increase in the number of rightward saccades and a decrease in their amplitude, and patients with left visual field defects showed a pattern more similar to that of the control subjects. Two patients showed a selective deficit in the range of medium-high spatial frequency; they were the only patients to show a lengthening of mean fixation time during reading. These results indicate selective effects on reading depending on primary sensory defects. The clinical relevance of these findings is briefly discussed.

Facilitatory effect of neglect rehabilitation on the recovery of left hemiplegic stroke patients: a cross-over study.

A study of the effect of specific training for visual neglect on the recovery of motor and functional impairment in stroke patients is reported. Two groups of right hemisphere stroke patients with hemispatial neglect and one group without neglect were assessed by means of three functional and neurological scales (Rivermead Mobility Index, Barthel Index, Canadian Neurological Scale). Three evaluations were made at 0, 2 and 4 months from the beginning of physical rehabilitation. During the first 2 months of physical rehabilitation one of the two groups of neglect patients was randomly assigned to specific training for neglect, and the second group to a general cognitive intervention; during the final 2 months of rehabilitation the types of training were switched in the two groups. The non-neglect patients improved steadily during physical rehabilitation. In contrast, the functional recovery of the two neglect groups was time-locked to the period of the specific training for neglect. At the time of admission, the two neglect groups performed at the same level; after 2 months of rehabilitation, the group with neglect training showed higher functional recovery than the group with only general cognitive intervention. When the latter group received neglect training, there was no longer any difference between the two neglect groups. This pattern was present for both of the functional scales used but not for the neurological scale. Motor and functional recovery of stroke patients with neglect seems to be significantly improved by the simultaneous presence of a treatment specifically focused on neglect.

Selective reading slowness in a traumatic patient with impairment in basic visual processes.

Following a closed-head injury, G.M., a 17-year-old male, showed a reading disturbance in the absence of other cognitive deficits. G.M.'s reading was exceedingly slow, although virtually error free. Analysis of his disorder indicated an inability to read words presented tachistoscopically to the left (spared) visual field. Therefore the reading deficit cannot be interpreted as simply due to the visual field reduction (hemianopic alexia). Reading speed was clearly affected by word length, a finding typical of letter-by-letter reading. Both behavioral and psychophysical testing indicated a selective reduction of visual discrimination and detection (particularly in the range of high spatial frequency information) in portions of the left hemifield which appeared spared upon perimetric examination. Overall, it is suggested that the reading deficit, phenomenologically similar to that of other letter-by-letter readers, can be interpreted as due to a combination of basic visual perturbations: visual field cut with macular splitting and deficit of processing of high spatial frequency information.

Local and global visual mechanisms underlying individual differences in the rod-and-frame illusion.

The role of local and global visual mechanisms in individual differences in the rod-and-frame (RF) effect was investigated. Field-dependent observes, selected on the basis of Witkin and Ash's (1948) classical procedure, were submitted to the small RF test (Coren & Holy, 1986). Four frame tilts and two gap sizes were used. As expected, direct effects (i.e., rod settings in the direction of frame tilt) were observed at small degrees of frame tilt, while indirect effects (i.e., rod settings in the direction opposite that of frame tilt) were observed at larger frame tilts. Field-dependent observers showed larger direct effects in the case of the small gap. Indirect effects were comparable in both field-dependent and field-independent subjects, regardless of gap size. Following the model proposed by Wenderoth and Johnstone (1987), these findings indicate that low-level visual mechanisms, responsible for local orientation interactions, have a different gain in field-dependent and field-independent individuals. In contrast, global visual mechanisms, presumably acting by means of long-range mechanisms, do not distinguish between these two subgroups.

Effectiveness of neglect rehabilitation in a randomized group study.

The effectiveness of neglect rehabilitation training has been studied in two randomly selected groups of right brain-damaged patients. All patients proved heminattentive on a standard battery 2 months or more after the CVA. One group received 2 months of treatment immediately after admission to a clinic, and the other group received only general cognitive stimulation for the same amount of time. At the end of this period a comparison showed significant improvement in the first group, based on a standard test battery and a functional scale. The second group was then given rehabilitation training for neglect for the same amount of time and obtained similar improvement. It is concluded that the rehabilitation program produces significant results, which generalize to situations similar to those of everyday life. The importance of the duration of training on the generalization of learning is briefly discussed with reference to previous negative reports in the literature.