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We document for the first time the effect of a spatial deficit on an spoken language task. Right brain-damaged patients with and without neglect were administered a task of emphatic stress. Patients listened to 60 subject-verb-object sentence pairs. The emphatic stress could be placed on the subject, on the verb or on the object word. Patients had to judge whether the two sentences were same or different for the position of the emphatic stress. The judgements were more impaired in patients with neglect and when the stress was placed at the beginning of the sentence (on the subject word), that is to say, at the leftmost location of a hypothetical spatial representation of the heard sentence. We hypothesize that auditory language undergoes a spatial transcoding, and that this transcoding is affected by the presence of a spatial bias like that observed in patients with neglect.

The existence of separate systems for processing geometric and non-geometric spatial information was studied. Twelve neglect patients were asked to reorient themselves in a room using only geometric information or to integrate this information with relevant visual cues both in the presence and in the absence of transcutaneous electrical neural stimulation (TENS). In the absence of TENS, all patients were greatly impaired in coding geometric information, and they had difficulty in coding non-geometric information. TENS significantly improved the ability to code shape-based representation, but is ineffective with non-geometric representations (such as color). The data support previous findings on neglect patients suggesting the presence of separate, independent neural systems subserving different types of space representation.

Optokinetic stimulation with left direction of the movement of luminous dots temporarily improved motor weakness of the left hand in two right-brain-damaged patients with left spatial hemineglect. Stimulation to the right had no effect. In two left-brain-damaged patients, optokinetic stimulation did not affect the right motor weakness, regardless of direction of the movement of the optokinetic stimuli. We suggest that in patients with left hemineglect, contralesional motor deficits have a neglect-related component, which, as other aspects of the neglect syndrome, may be improved by optokinetic stimulation. The mechanisms may include a temporary restoration of the spatial coordinates of bodily representations, pathologically distorted towards the side of the lesion.

The present study quantitatively investigated the slow and quick phases of optokinetic nystagmus (OKN) in four groups of patients: right unilateral brain-damaged patients with neglect, left and right patients without neglect or hemianopia and patients with left or right retrogeniculate lesions and lateral homonymous hemianopia. Our results indicate that only neglect patients show a perturbation of both components of OKN. A comparison among MRI images of different patients shows that a region involving area 37 and adjacent areas 39 and 19, was impaired in all patients with neglect, but not in any other patient with either right or left lesions.

Contrasting hypotheses have been proposed about the functional equivalence between waking saccades and REMs. Patients with left visual hemi-inattention showed dissociation between the direction of waking saccades and that of REMs. REMs directed toward the left were virtually absent, while waking inspective saccades directed in both lateral directions were present, but confined to the right hemispace. It is concluded that: a) the cortical areas regulating attention are relevant in the production of REMs; b) two separate attentional mechanisms have to be considered in relation to the hemi-inattentive syndrome, one is involved in the cognitive control of visual exploration and plays little or no role in the modulation of REMs, the other deals with REMs during sleep and with reflex-like orienting responses to peripheral stimuli during waking.