Development of neuropsychiatric symptoms in poststroke patients: a cross-sectional study.

OBJECTIVE: The study aimed to characterize neuropsychiatric symptomatology and its evolution in a large group of poststroke patients during their first year. METHOD: The Neuropsychiatric Inventory (NPI) was administered to a sample of 124 poststroke patients, divided into three independent groups on the basis of time from stroke (2, 6 and 12 months). The controls were 61 healthy subjects. RESULTS: A wide range of neuropsychiatric symptoms was found significant in the poststroke population: mostly depression (61%), irritability (33%), eating disturbances (33%), agitation (28%), apathy (27%) and anxiety (23%). Modifications in terms of greater depression, anxiety, irritability and eating disturbances evolved in the year following stroke. Other symptoms were significantly present depending on time from stroke. Clear relations with other clinical and demographic variables were also found. CONCLUSION: Neuropsychiatric symptoms constitute an important part of comorbidity in stroke patients; thus, suitable assessment tools may improve clinical understanding of these patients.

Misrepresentation of horizontal space in left unilateral neglect: role of hemianopia.

BACKGROUND: Right-brain-damaged patients with left unilateral neglect are reported to misperceive the horizontal extension of contralesional stimuli as being shorter than that of ipsilesional stimuli. OBJECTIVE: To investigate the functional and anatomic correlates of horizontal space misrepresentation. METHODS: Eight right-brain-damaged patients with contralesional neglect and complete hemianopia (N+H+), nine right-brain-damaged patients with contralesional neglect and no visual field defect (N+H-), and five unilateral brain-damaged patients with contralesional complete hemianopia and no neglect (N-H+) reproduced a horizontal distance (10 cm) in the contralesional and ipsilesional hemispace. RESULTS: N+H+ patients overextended the distance contralesionally and underextended the same distance ipsilesionally. N+H- and N-H+ patients reproduced equivalent distances contralesionally and ipsilesionally. Compared with N+H- patients, N+H+ patients had a greater ipsilesional shift when bisecting horizontal lines; however, these two groups of patients had comparable neglect severity on multiple-item cancellation tasks. In the N+H+ group the area of maximal overlapping of the lesion was in the posterior cerebral lobes. CONCLUSION: Complete contralesional hemianopia after posterior brain damage is an important factor in determining misrepresentation of horizontal space in patients with left unilateral neglect.

Contrast sensitivity loss in the neglected hemifield.

Contrast sensitivity to gratings of various spatial frequencies displayed in the left and right visual hemifield was measured in a group of ten right brain-damaged patients with unilateral visuospatial neglect. Two groups of ten left brain-damaged (LBD) and ten right brain-damaged (RBD) patients without neglect served as controls. All patients had normal visual fields according to standard clinical procedure. Stimuli were patches of sinusoidal gratings of 1, 2, 4 and 8 c/deg spatial frequency. The patches subtended 6 deg and were displayed at 3 deg of eccentricity. A two-alternative forced-choice technique was employed. Results showed a reduction in contrast sensitivity for stimuli presented to the contralesional hemifield with respect to the ipsilesional hemifield in patients with neglect. No difference in contrast sensitivity between hemifields was found for LBD and RBD groups. These findings indicate a basic visual impairment in the contralesional hemifield in patients with neglect.

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.

Early visual processing in neglect patients: a study with steady-state VEPs.

Reliable steady-state visual evoked potentials (VEPs) were recorded in a group of 19 right brain-damaged patients with visuospatial hemineglect (Neglect), and two control groups: 15 left brain-damaged (LBD) patients and 12 right brain-damaged (RBD) patients without neglect. Moreover, VEPs were recorded in two rare cases of left brain damage and right visuospatial hemineglect. Stimuli were gratings phase-reversed at various temporal frequencies presented in the left and right visual field. In the Neglect group, VEPs to stimuli displayed in the left visual field (contralesional stimuli) had longer latencies. The delay was not present for the two control groups. As regards the VEP amplitudes, the Neglect group data showed a less distinctive pattern than in the case of latency. VEPs to stimuli contralateral to the lesion were smaller than those recorded for stimuli ipsilateral to the lesion in both Neglect and RBD groups. On the contrary, the VEP amplitudes for the two hemifields were comparable in the LBD group. In the case of left brain damage and neglect, VEPs to right visual field stimuli had longer latencies and lower amplitudes compared to the ipsilesional responses in both patients. Overall, the data support the view that, in most cases, early visual processing is not intact in the neglected hemifield.

Neglect for low luminance contrast stimuli but not for high colour contrast stimuli: a behavioural and electrophysiological case study.

We describe a patient with a right hemisphere lesion involving the frontal lobe, the post-central gyrus and the superior parietal lobule. Behavioural testing demonstrated severe left unilateral neglect to low luminance contrast stimuli, but not to high colour contrast stimuli. Evoked potentials to low contrast luminance gratings presented in the left hemifield were not reliable. However, equiluminant coloured gratings presented in the same hemifield evoked reliable electrophysiological responses, although longer in latency than those evoked in the right hemifield. These findings suggest that the patient has severe damage of the high contrast sensitivity magnocellular pathway in the right hemisphere, with minor involvement of the parvocellular pathway.

VEP in neglect patients have longer latencies for luminance but not for chromatic patterns.

In patients with unilateral neglect, visual evoked potentials (VEP) to stimuli displayed in the left visual field are delayed compared with responses to right visual field stimuli. In the present study, 10 patients with right brain damage and neglect were tested with contrast-reversed sinusoidal gratings, modulated either in luminance or in chromaticity. For gratings of luminance contrast modulated over relatively high temporal frequencies (4-10.5 Hz), latencies of VEP were about 30 ms longer for stimuli presented to the contralesional (left) visual field than to the field ipsilateral to the lesion. For equiluminant stimuli modulated at relatively low temporal frequencies (1-4 Hz), however, latency was the same for both hemifields. As this condition activates predominately the parvocellular pathway the results are consistent with our previous suggestion that the delay observed with luminance stimuli in neglect patients results from selective disruption of the faster response of the magnocellular pathway.