Rosaleen A. McCarthy

Past, present, and prospects: Reflections 40 years on from the selective impairment of semantic memory (Warrington, 1975)

We summarize the main findings and conclusions of Warringtons (1975) paper, The Selective Impairment of Semantic memory, a neuropsychological paper that described three cases with degenerative neurological conditions [Warrington, E. K. (1975). The selective impairment of semantic memory. The Quarterly Journal of Experimental Psychology, 27, 635–657]. We consider the developments that have followed from its publication and give a selective overview of the field in 2014. The initial impact of the paper was on neuropsychological investigations of semantic loss followed some 14 years later by the identification of Semantic Dementia (the condition shown by the original cases) as a distinctive form of degenerative disease with unique clinical and pathological characteristics. We discuss the distinction between disorders of semantic storage and refractory semantic access, the evidence for category- and modality-specific impairments of semantics, and the light that has been shed on the structure and organization of semantic memory. Finally we consider the relationship between semantic memory and the skills of reading and writing, phonological processing, and autobiographical memory.

Bilingual aphasia due to spontaneous acute subdural haematoma from a ruptured intracranial infectious aneurysm

We report a case of spontaneous subdural haematoma due to ruptured intracranial infectious aneurysm, presenting with bilingual aphasia and illustrating differential language recovery. A 62-year-old right-handed bilingual gentleman, with a diagnosis of infective endocarditis, developed headache and became expressively aphasic in the English language. Three days later he was receptively and expressively aphasic in both English and Arabic. Cranial MRI scans showed a left-sided acute subdural haematoma with mass effect and midline shift. Contrast CT brain scans showed an enhancing speck adjacent to the clot and cerebral angiogram confirmed a distal middle cerebral artery aneurysm. He underwent image-guided craniotomy, evacuation of the subdural haematoma and excision of the aneurysm. Histopathological examination was consistent with an infectious intracranial aneurysm. Postoperatively his aphasia did not improve immediately. He had widened pulse pressure due to severe aortic regurgitation, confirmed on echocardiography. He underwent aortic valve replacement and mitral valve repair, following which his aphasia recovered gradually. Initially the recovery of his language was limited to Arabic. About a week later he recovered his English language as well. At 3-year follow-up he is doing well and has no neurological deficits. His aphasia has recovered completely. The present case is unique because of (a) presence of pure subdural haematoma, and (b) the differential susceptibility and recovery of native (L1) and acquired language (L2) in presence of a common pathology. The neurology of language in a bilingual is analysed and possible mechanisms discussed.

The Role of Configurality in the Thatcher Illusion: An ERP Study

The Thatcher illusion (Thompson in Perception, 9, 483–484, 1980) is often explained as resulting from recognising a distortion of configural information when ‘Thatcherised’ faces are upright but not when inverted. However, recent behavioural studies suggest that there is an absence of perceptual configurality in upright Thatcherised faces (Donnelly et al. in Attention, Perception & Psychophysics, 74, 1475–1487, 2012) and both perceptual and decisional sources of configurality in behavioural tasks with Thatcherised stimuli (Mestry, Menneer et al. in Frontiers in Psychology, 3, 456, 2012). To examine sources linked to the behavioural experience of the illusion, we studied inversion and Thatcherisation of faces (comparing across conditions in which no features, the eyes, the mouth, or both features were Thatcherised) on a set of event-related potential (ERP) components. Effects of inversion were found at the N170, P2 and P3b. Effects of eye condition were restricted to the N170 generated in the right hemisphere. Critically, an interaction of orientation and eye Thatcherisation was found for the P3b amplitude. Results from an individual with acquired prosopagnosia who can discriminate Thatcherised from typical faces but cannot categorise them or perceive the illusion (Mestry, Donnelly et al. in Neuropsychologia, 50, 3410-3418, 2012) only differed from typical participants at the P3b component. Findings suggest the P3b links most directly to the experience of the illusion. Overall, the study showed evidence consistent with both perceptual and decisional sources and the need to consider both in relation to configurality.

Higher-order semantic processing in formal thought disorder in schizophrenia

Higher-order semantic impairments and lack of sensitivity to linguistic context have both been implicated in formal thought disorder (FTD) in schizophrenia. Most investigations have focused on comprehension. We investigated the processing of higher-order semantic relations and the role of emotional arousal in FTD patients linguistic comprehension and production. We compared FTD schizophrenia patients (n=14) with non-FTD schizophrenia patients (n=18) and healthy controls (n=15) on sense-judgment and repetition tasks, in emotionally negative and neutral conditions. We predicted that the FTD group would display poor sensitivity compared to the other two groups in comprehension and production, and that this would be exacerbated by sentence complexity and negative emotional arousal. The emotional manipulation was not robustly successful, and did not affect task performance in the patient groups. FTD patients made significantly more errors on sense-judgments and repetition than the other two groups. Complexity affected all groups to a similar extent in sense-judgments, but affected FTD patients disproportionately in the repetition task. These results support the view that a lack of sensitivity to context underlies FTD in comprehension and production stages of processing. Patients fail to utilise linguistic context to integrate lexical forms into a global whole and guide their access to lexical targets.

Verbatim recall in formal thought disorder in schizophrenia: a study of contextual influences

Introduction We have previously reported that people with schizophrenia and formal thought disorder (FTD) were disproportionately impaired in recalling sentences verbatim and in judging their plausibility. We proposed that these deficits were due to impairment in integrating higher-order semantic information to construct a global whole. However, it is also possible that a lower-level linguistic problem affecting lexical activation could account for this pattern. Methods The present study analysed and compared the sentence repetition errors produced by people with FTD, people with schizophrenia who were non-FTD and healthy controls. Errors due to failure of activation of the target lexical items were differentiated from those due to erroneous integration of information. Results People with FTD produced significantly more unrelated lexical substitutions and omissions in their corpora than the other two groups, indicating an impairment of activation. In addition, they made significantly more erroneous contextual inferences and unrelated references, suggesting they were impaired in reconstructing the global whole from successfully activated items. Conclusion These findings are consistent with a dual process account of impairments in FTD. Difficulties in repeating and judging sentence acceptability arises due to a combination of difficulty with activation and deficits in using linguistic context to process and produce speech. It is suggested that processing difficulties in FTD result from an impairment in using semantic context to drive lexical access and construction of a global whole.

Discriminating Thatcherised from typical faces in a case of prosopagnosia

We report data from a prosopagnosic patient (PHD), and aged-matched control participants, from experiments where participants categorised individually presented emotional faces (experiment 1) and Thatcherised (from typical) faces (experiment 2). In experiment 2 participants also discriminated between simultaneously presented Thatcherised and typical faces. PHD was at chance categorising Thatcherised from typical faces. He was, however, able to discriminate between Thatcherised and typical faces, and partially able to categorise emotional faces. The results are discussed in terms of a loss of configural processing but preserved feature processing in PHD. The loss of configural processing impacts his categorisation of Thatcherised and typical faces, and his emotion processing, while his preserved feature processing supports his ability to categorise some emotional faces and his ability to discriminate between Thatcherised and typical faces.

Transient Retrograde Amnesia: a focal and selective (but temporary) loss of memory for autobiographical events.

Transient memory disorders are not all global. Temporary disruption may affect procedural knowledge (Stracciari, Guarino, & Pazzaglia, 1997), semantic memory (Hodges, 1997); verbal learning and memory (Nishiyama, Kurisaki, Bandoh, Ishikawa, & Sugishita, 1993); autobiographical knowledge (Venneri& Caffarra, 1998); people (Kapur, Katifi, elZawawi, Sedgwick, & Barker, 1994) and topographical orientation (Gil-N eciga et al., 2002). We have recently learned of a case of focal Transient Retrograde Amnesia (TRAM) that appears to have spared the patients anterograde memory as well as retrograde familiarity for friends and family. Frances is a 62 year old, right handed retired professional woman who has been under investigation at the Wessex Neurological Unit following three episodes of transient global amnesia (TGA). In 2011 she had been investigated for paraesthesia and vertigo, undergoing an MRI scan. The first episode of TGA (13/03/12) lasted for approximately 4 h and occurred at a family funeral: Frances repeatedly greeted the same friends as if they had just arrived and repetitively asked whether certain people were going to attend. She made a full recovery. After the event, Frances listened to a CD recording of the funeral but did not experience any recognition. Two further, similar episodes of TGA occurred in May and August 2014. The episode of Transient Retrograde Amnesia (TRAM) occurred at the reception following another family funeral (15/ 09/14). Francess TRAM event differed very clearly from the previous three TGA occurrences due to sparing of Francess anterograde memory and new learning: There was no repetitive questioning Frances clearly remembered the immediate past and present Oldermemories from the previous day and earlier were not retrieved.

Language abnormality in deaf people with schizophrenia: a problem with classifiers

ABSTRACT Introduction: Although there is evidence for language abnormality in schizophrenia, few studies have examined sign language in deaf patients with the disorder. This is of potential interest because a hallmark of sign languages is their use of classifiers (semantic or entity classifiers), a reference-tracking device with few if any parallels in spoken languages. This study aimed to examine classifier production and comprehension in deaf signing adults with schizophrenia. Method: Fourteen profoundly deaf signing adults with schizophrenia and 35 age- and IQ-matched deaf healthy controls completed a battery of tests assessing classifier and noun comprehension and production. Results: The patients showed poorer performance than the healthy controls on comprehension and production of both nouns and entity classifiers, with the deficit being most marked in the production of classifiers. Classifier production errors affected handshape rather than other parameters such as movement and location. Conclusions: The findings suggest that schizophrenia affects language production in deaf patients with schizophrenia in a unique way not seen in hearing patients.

A possible marker of configural processing at the N170: Converging evidence from typical participants and a case of prosopagnosia

Both orientation and Thatcherisation are thought to influence configural processing in faces (Boutsen, Humphreys, Praamastra & Warbrick, 2006). We explored the effect of orientation and level of Thatcherisation (typical face, eyes Thatcherised, mouth Thatcherised, or both features Thatcherised) on early ERP components. Participants showed evidence of inversion effects leading to increased amplitude for inverted faces at the N170 and reduced amplitude to inverted faces at the P2. However, the effect of Thatcherisation was only evident in the right hemisphere N170 where there was a reduction in N170 amplitude with level of Thatcherisation. These data suggest two distinct processes (consistent with Towler, Gosling, Duchaine, & Eimer, 2012). In a follow-up study using the same task we tested PHD, an individual with acquired prosopagnosia known to be unable to perceive the Thatcher illusion (Mestry, Donnelly, Menneer & McCarthy, 2012). We did so to explore whether the markers of orientation and Thatcherisation would survive in the ERP in the absence of sensitivity to the Thatcher illusion. PHD did show a significant effect of inversion at both the N170 and P2. However, PHD produced no effect of Thatcherisation at the N170, in contrast to the effect found with typical participants. The results suggest that the effect of Thatcherisation manifest in the right hemisphere N170 underpins the perception of the Thatcher illusion. As the effects of orientation at the N170 and P2 are also found in an individual who does not perceive the illusion, then they cannot reflect the type of configural processing affected by the Thatcher illusion (Donnelly, Cornes and Menner, 2012). In conclusion, the novel N170 Thatcherisation effect is a marker of a kind of configural processing present in typical face processing that is affected by Thatcherisation (Mestry, Menneer, Wenger, & Donnelly, 2012).

Detecting the Thatcher illusion in a case of prosopagnosia

We explored configural face processing in a prosopagnosic patient (PHD, Eimer and McCarthy, 1999) who does not produce an N170 is response for faces. In two sets of studies he was presented with two versions of the Thatcher illusion. In the first set, he was asked to detect Thatcherized from matched typical faces from successive single presentations of faces. He also performed a simultaneous 2 alternative forced choice (2AFC) discrimination task with the same stimulus set to address the question of whether pairs of faces were the same or different. In the second set he was asked to detect Thatcherized from matched typical faces. He also performed in control conditions where orientation decisions were made to isolated eye and mouth features, as well as eye and mouth features presented alone but within face outlines. The results were analyzed using d-prime and C to facilitate cross condition comparisons. The data showed PHD unable to detect Thatcherized from matched typical faces in either study 1 or 2. However, he was as sensitive as controls in the 2AFC discrimination condition of Study 1. In study 2 he showed evidence of moderate sensitivity to the identification of orientation for isolated features; this sensitivity was much enhanced for eyes by face outlines but hindered for mouths. We interpret these findings as showing intact feature processing that should be sufficient to allow the detection of the Thatcher illusion, as well as some evidence of relational processing for eyes but not mouths. However, simultaneous presentation of features and face outline does not allow selective attention to eyes that would enable detection of Thatcherized from matched typical faces. The results suggest one aspect of successful face categorization is to determine face-specific configural routines that allocate attention within faces and that these are missing in PHD.