Freda Newcombe

Patterns of paralexia: A psycholinguistic approach

A sample of the literature on acquired dyslexia is reviewed with special reference to the nature of paralexic errors. Linguistic studies of six cases of dyslexia are presented, with appropriate neurological and psychological details; there are two cases of each of three hypothesized types of impairment, visual dyslyxia, “surface” (grapheme-phoneme) dyslexia, and “deep” (syntactico-semantic) dyslexia. Finally, a scheme for acquired dyslexia is proposed and related to the error patterns observed in “normal” adult readers and in children learning to read; our approach to lexical look-up is one that the diagram makers may have found sympathique.

Syntactic and semantic errors in paralexia

Abstract A case of selective dysphasic impairment resulting from gunshot injury is reported. The numerous paralexic errors made to different parts of speech are analysed. The preponderance of semantic errors and specific facilitation of noun responses are discussed.

Face recognition without awareness

Abstract PH has been completely unable to recognise faces since sustaining a closed head injury some four years ago, but can recognise familiar people from their names. His performance on face processing tasks is, however, comparable to that of normal subjects if explicit recognition is not required. Thus he can make same/different identity judgements more quickly for familiar than unfamiliar face photographs, and faster matching of familiar faces is only found for identity matches involving the faces internal features. When making semantic categorisation decisions to printed names he shows interference from distractor faces belonging to an incorrect category, even when the faces in each category are matched on physical appearance. When learning to associate the occupation or the name with photographs of faces, his performance is better with true (face and persons actual name or occupation) than untrue (face and another persons name or occupation) pairings. Covert recognition can also be demonstrated f...

Impairment of auditory perception and language comprehension in dysphasia

Abstract Men with chronic focal brain wounds were examined for their ability to discriminate complex tones, synthesized steady-state vowels, and synthesized consonant—vowel syllables. Subjects with left hemisphere damage, but not right hemisphere damage, were impaired in their ability to respond correctly to rapidly changing acoustic stimuli, regardless of whether stimuli were verbal or nonverbal. The degree of impairment in auditory processing correlated highly with the degree of language comprehension impairment. The pattern of impairment of the group with left hemisphere damage on these perceptual tests was similar to that found in children with developmental language disorders.

Handedness, speech lateralization and ability.

Abstract Data on verbal and performance tasks are presented from a large sample of the normal population and from a group of men with chronic unilateral cerebral lesions due to missile injury. It is suggested that: 1. ( a )|unselected groups of left-handers in the normal population perform as well as right-handers on standard cognitive tasks; 2. ( b )|non-right-handed men with unilateral cerebral lesions are not less impaired in verbal and performance tasks than a comparable right-handed group; 3. ( c )|unusual patterns of cerebral organisation may be associated with non-familial sinistrality and pure left-handedness.

Dissociable visual and spatial impairments following right posterior cerebral lesions: Clinical, neuropsychological and anatomical evidence

A double dissociation of visual and spatial performance is reported in two men with chronic focal missile injuries of the right cerebral hemisphere. The clinical, neuropsychological and post-mortem anatomical data are considered in relation to evidence from physiological research of two major cortico-cortical pathways for object-recognition and spatial perception.

Faces interfere with name classification in a prosopagnosic patient

Since sustaining a severe closed head injury P.H. has been completely unable to recognise familiar faces, but remains able to identify written names. Despite his inability to recognise faces overtly, P.H. nevertheless shows a normal pattern of interference from simultaneously presented distractor faces in a politician vs nonpolitician name classification task. His reaction times for semantic (politician versus nonpolitician) classification of printed names are slowed by the presence of a face drawn from the incorrect semantic category. This interference is found even though P.H. performs at chance level when asked to overtly classify the faces used in the task. The finding demonstrates that prosopagnosic patients may covertly achieve relatively precise recognition of familiar faces and access to semantic information.

A Left Hemisphere Contribution to Visuospatial Processing

Men with chronic, focal, unilateral missile injures of the brain--twenty-five with left hemisphere lesions (LH group) and twenty with right hemisphere lesions (RH groups)--and twenty-two control subjects were given two visuoperceptual and two visuospatial tests. The LH group was significantly impaired in relation to the control group on both the spatial tasks. A different pattern of dissociable perceptual and spatial deficits was found in the experimental groups: better preserved perceptual than spatial performance was observed more frequently in the LH group whereas the converse--relatively better spatial than perceptual performance--was more evident in the RH group. Double dissociations in performance on the two spatial tasks were found predominantly in the LH group. These findings suggest an important left hemisphere contribution to visuospatial processing and the possibility of a more focal representation of spatial abilities in the left hemisphere than in the right.

Chromatic Discrimination in a Cortically Colour Blind Observer

We tested the ability of a subject with cerebral achromatopsia to discriminate between colours and to detect chromatic borders. He was unable to identify colours or to arrange them in an orderly series or choose the odd colour out of an array or even to pick out a colour embedded in an array of greys. Nevertheless, he could select the odd colour when the colours were contiguous, even when they were isoluminant, and could discriminate an ordered from a disordered chromatic series as long as the colours in each row abutted one other. His verbal replies showed that he did so by detecting an edge between two stimuli that were, to him, perceptually identical. Introducing a narrow isoluminant grey stripe between adjacent colours abolished or greatly impaired this ability. As long as isoluminant colours were contiguous the patient could identify the orientation of the chromatic borders. Photopic spectral sensitivity showed evidence both for activity of three cone channels and for chromatic opponent processing, indicating that postreceptoral chromatic processing is occurring despite the absence of any conscious awareness of colour. The results indicate that both parvocellular colour opponent and magnocellular broad‐band channels are active and that the cortical brain damage has selectively disrupted the appreciation of colour but not the ability to detect even isoluminant chromatic borders, which would be invisible to a retinal achromat. The subjects performance on non‐colour tasks involving the discrimination of shape, texture, greyness and position was excellent. His disorder is therefore not like that of macaque monkeys in which cortical area V4 has been removed, and which are much more severely impaired at discriminating shape than colour.

A dissociation between the sense of familiarity and access to semantic information concerning familiar people

Abstract Functional models that describe the underlying processes involved in normal face perception and recognition postulate separate stages for the classification of a face as familiar and for the retrieval of semantic information concerning the bearer of the face. On the assumption that these stages can be selectively affected by neurological disease, the models predict the existence of brain-injured patients who may remain able to decide whether a face is familiar or not, but who cannot access person information such as occupation, etc. This possibility is investigated in a patient, ME, with a pure amnesic syndrome including severe anterograde and retrograde long-term memory loss. Performance on tasks requiring the matching of unfamiliar faces and judging the familiarity of faces or names was normal for ME, but she was very poor at giving relevant semantic information to identify faces or names she found familiar. These findings support current neuropsychological and simulation models of face processing.