Longitudinal assessment of short-term memory deterioration in a logopenic variant primary progressive aphasia with post-mortem confirmed Alzheimer's Disease pathology.

In the field of dementia research, there are reports of neurodegenerative cases with a focal loss of language, termed primary progressive aphasia (PPA). Currently, this condition has been further sub-classified, with the most recent sub-type dubbed logopenic variant (PPA-LV). As yet, there remains somewhat limited evaluation of the characteristics of this condition, with no studies providing longitudinal assessment accompanied by post-mortem examination. Moreover, a key characteristic of the PPA-LV case is a deterioration of phonological short-term memory, but again little work has scrutinized the nature of this impairment over time. The current study seeks to redress these oversights and presents detailed longitudinal examination of language and memory function in a case of PPA-LV, with special focus on tests linked to components of phonological short-term memory function. Our findings are then considered with reference to a contemporary model of the neuropsychology of phonological short-term memory. Additionally, post-mortem examinations indicated Alzheimer's disease type pathology, providing further evidence that the PPA-LV presentation may reflect an atypical presentation of this condition.

Eighteen years on: What next for the PALPA?

The Psycholinguistic Assessments of Language Processing Abilities (PALPA) is a battery of tests designed to assess language processing abilities in individuals with acquired aphasia. Published in 1992, the battery was well-received by both clinicians and researchers, yet no revised version has been published to date. In this paper, we examine contemporary usage of the PALPA in both clinical and research settings, to inform decisions regarding future developments of the resource. First, we carried out a literature search to identify all published papers that have cited the PALPA since 2003, and compared our findings to those from an earlier search covering the period from 1991 to 2002. Second, we created an online survey that examined current usage of the PALPA in both clinicians and researchers. Our findings suggest the PALPA continues to be a well-used tool in both clinical and research settings, but could benefit from some improvements in its content and presentation. Further, there are time constraints in administering the PALPA, indicating an additional component for general-screening purposes would be a welcome extension to the battery.

Positive and negative emotion enhances the processing of famous faces in a semantic judgment task.

Previous work has consistently reported a facilitatory influence of positive emotion in face recognition (e.g., D'Argembeau, Van der Linden, Comblain, & Etienne, 2003). However, these reports asked participants to make recognition judgments in response to faces, and it is unknown whether emotional valence may influence other stages of processing, such as at the level of semantics. Furthermore, other evidence suggests that negative rather than positive emotion facilitates higher level judgments when processing nonfacial stimuli (e.g., Mickley & Kensinger, 2008), and it is possible that negative emotion also influences latter stages of face processing. The present study addressed this issue, examining the influence of emotional valence while participants made semantic judgments in response to a set of famous faces. Eye movements were monitored while participants performed this task, and analyses revealed a reduction in information extraction for the faces of liked and disliked celebrities compared with those of emotionally neutral celebrities. Thus, in contrast to work using familiarity judgments, both positive and negative emotion facilitated processing in this semantic-based task. This pattern of findings is discussed in relation to current models of face processing.

Visuoperceptual deficits in letter-by-letter reading?

A longstanding and controversial issue concerns the underlying mechanisms that give rise to letter-by-letter (LBL) reading: while some researchers propose a prelexical, perceptual basis for the disorder, others postulate a postlexical, linguistic source for the problem. To examine the nature of the deficit underlying LBL reading, in three experiments, we compare the performance of seven LBL readers, matched control participants and one brain-damaged patient, OL, with no reading impairment. Experiment 1 revealed that the LBL patients were impaired, relative to the controls and to OL, on a same/different matching task using checkerboards of black and white squares. Given that the perceptual impairment extends beyond abnormalities with alphanumeric stimuli, the findings are suggestive of a more general visual processing deficit. This interpretation was confirmed in Experiments 2 (matching words and symbol strings) and 3 (visual search of letter and symbol targets), which compared the processing of linguistic and non-linguistic written stimuli, matched for visual complexity. In both experiments, the LBL patients displayed qualitatively similar effects of length and left-to-right sequential ordering on linguistic and non-linguistic stimuli. Moreover, there was a clear association between the perceptual impairments on these tasks and the slope of the reading latency function for the LBL patients. Taken together, these findings are consistent with a significant visuoperceptual impairment in LBL that adversely affects reading performance as well as performance on other non-reading tasks.

Dysgraphia in dementia: a systematic investigation of graphemic buffer features in a case series.

In this paper we report findings from a systematic investigation of spelling performance in three patients - PR, RH and AC - who despite their different medical diagnoses showed a very consistent pattern of dysgraphia, more typical of graphemic buffer disorder. Systematic investigation of the features characteristic of this disorder in Study 1 confirmed the presence of length effects in spelling, classic errors (i.e., letter substitution, omission, addition, transposition), a bow-shaped curve in the serial position of errors and consistency in substitution of consonants and vowels. However, in addition to this clear pattern of graphemic buffer impairment, evidence of regularity effects and phonologically plausible errors in spelling raised questions about the integrity of the lexical spelling route in each case. A second study was conducted, using a word and non-word immediate delay copy task, in an attempt to minimise the influence of orthographic representations on written output. Persistence of graphemic buffer errors would suggest an additional, independent source of damage. Two patients, PR and AC, took part and in both cases symptoms of graphemic buffer disorder persisted. Together, these findings suggest that damage to the graphemic buffer may be more common than currently suggested in the literature.

Longitudinal assessment of language and memory impairments in pathologically confirmed cortico-basal ganglionic degeneration.

We report a longitudinal case study (patient EP) of histologically confirmed cortico-basal ganglionic degeneration (CBD) who presented with non-fluent progressive aphasia (NFPA). While NFPA has been documented in clinical descriptions of other reports of CBD, details are often limited and the majority of studies are cross-sectional in nature. The present study conducted detailed longitudinal assessment with EP over a period of two years that revealed substantial impairments of episodic memory, semantic memory, naming and particular aspects of reading and spelling. Our investigations identify key features of EP's pattern of impairment that warrant further examination with other cases of CBD. In particular, testing of EP's nonword reading and spelling found that both were impaired and declined over time. In addition, verbal recognition deteriorated faster than non-verbal recognition through the course of the disease. Our review of the literature suggests that poor nonword reading and spelling may be consistent features of CBD, but more studies are needed to confirm this suggestion, and to determine whether they warrant inclusion in profiling CBD.

Does maintenance of colour categories rely on language? Evidence to the contrary from a case of semantic dementia.

Recent neuropsychological evidence, supporting a strong version of Whorfian principles of linguistic relativity, has reinvigorated debate about the role of language in colour categorisation. This paper questions the methodology used in this research and uses a novel approach to examine the unique contribution of language to categorisation behaviour. Results of three investigations are reported. The first required development of objective measures of category coherence and consistency to clarify questions about healthy control performance on the freesorting colour categorisation task used in previous studies. Between-participant consistency was found to be only moderate and the number of colour categories generated was found to vary markedly between individuals. The second study involved longitudinal neuropsychological examination of a patient whose colour categorisation strategy was monitored in the context of a progressive decline in language due to semantic dementia. Performance on measures of category coherence and consistency was found to be relatively stable over time despite a profound decline in the patient's colour language. In a final investigation we demonstrated that, for both the patient and controls, between- and within-participant consistency were higher than expected by (a) random sorting and (b) sorting perceptually similar chips together. These findings indicate that the maintenance of colour categorisation need not depend on language.

Neuropsychological and psychiatric profiles in acute encephalitis in adults.

Acute encephalitis is an inflammation of brain tissue that can result from activity in the central nervous system (CNS) of a number of viruses. Although the neurological and psychiatric effects of encephalitis in the acute phase of the illness are well-known (Caroff, Mann, Gliatto, Sullivan, & Campbell, 2001), larger scale studies of the pattern of neuropsychological and psychiatric impairment following recovery from the acute inflammatory phase are less apparent. This paper reports the results of neuropsychological testing with a range of standardised cognitive measures in a case series of long-term post-acute participants. Psychiatric abnormality is examined using the SCL-90-R self-report scale of distress (Derogatis, 1983). We also examined the role of emerging insight in the aetiology of depression in this population. Two clusters of cognitive dysfunction were observed, one group of primarily herpes simplex cases showing a severe generalised deficit across a number of cognitive domains and a second cluster showing a variety of more isolated disorders of executive function. Abnormally high levels of distress were reported by participants, with depression, obsessive-compulsive symptoms, interpersonal sensitivity and phobic anxiety most significantly increased. Depression was found to be least severe in those with most accurate insight into their problems. Examining the correlations between cognitive and psychiatric test results demonstrates a relationship between depression and interpersonal anxiety and specific cognitive measures. Obsessive-compulsive behaviour and phobic anxiety, however, appear to exist independently of the assessed cognitive deficits.

Phonological dyslexia and phonological impairment: an exception to the rule?

The condition known as phonological dyslexia involves very poor reading of non-words, with otherwise good word reading performance [e.g. Derouesné & Beauvois, 1979; Sartori, G., Barry, C., & Job, R. (1984). Phonological dyslexia: A review. In R. N. Malatesha & H. A. Whitaker (Eds.), Dyslexia: A global issue. The Hague: Martinus Nijhoff Publishers]. Theoretical accounts of this non-word reading impairment suggest disruption to either a component of a non-lexical orthographic-phonological reading route [that is specifically involved in reading non-words; Coltheart, M., Rastle, K., Perry, C., Langdon, R., & Zeigler, J. (2001). A dual route cascaded model of visual word recognition and reading aloud. Psychological Review, 108, 204-256] or to generalised phonological processes on which novel reading is heavily dependent [Farah, M., Stowe, R. M., & Levinson, K. L. (1996). Phonological dyslexia: Loss of a reading-specific component of cognitive architecture? Cognitive Neuropsychology, 13, 849-868; Harm, M. W., & Seidenberg, M. S. (1999). Phonology, reading acquisition, and dyslexia: Insights from connectionist models. Psychological Review, 106, 491-528]. The present paper questions the latter hypothesis: that phonological dyslexia always occurs in connection with some other form of phonologically based disruption (i.e. in a 'cluster' of impairments that are not necessarily reading-specific). Contrary to this view, several recent studies have reported that phonological dyslexia can occur without corresponding generalised phonological impairment [e.g. Caccappolo-van Vliet, E., Miozzo, M., & Stern, Y. (2004a). Phonological dyslexia without phonological impairment? Cognitive Neuropsychology, 21, 820-839; Caccappollo-van Vliet, E., Miozzo, M., & Stern, Y. (2004b). Phonological dyslexia: A test case for reading models. Psychological Science, 15, 583-590]. However, the work is subject to a number of criticisms. The following study examines performance of a phonological dyslexic case (JH) on a variety of phonological based tasks and, unlike many other studies, components of phonological short-term memory. Despite clear impairments in reading non-words, good performance on a variety of phonological tasks makes the possibility of generalised phonologically based disruption unlikely. The view that JH's good phonological skill was dependent on the use of spelling based strategies was also excluded. As a result, JH's pattern of performance provides clear evidence that phonological dyslexia can occur without any generalised phonological impairment.

Selective preservation of memory for people in the context of semantic memory disorder: patterns of association and dissociation.

A number of single cases in the literature demonstrate that person-specific semantic knowledge can be selectively impaired after acquired brain damage compared with that of object categories. However, there has been little unequivocal evidence for the reverse dissociation, selective preservation of person-specific semantic knowledge. Recently, three case studies have been published which provide support for the claim that such knowledge can be selectively preserved [Kay, J., & Hanley, J. R. (2002). Preservation of memory for people in semantic memory disorder: Further category-specific semantic dissociation. Cognitive Neuropsychology, 19, 113-134; Lyons, F., Hanley, J. R., & Kay, J. (2002). Anomia for common names and geographical names with preserved retrieval of names of people: A semantic memory disorder. Cortex, 38, 23-35; Thompson, S. A, Graham, K. S., Williams, G., Patterson, K., Kapur, N., & Hodges, J. R. (2004). Dissociating person-specific from general semantic knowledge: Roles of the left and right temporal lobes. Neuropsychologia, 42, 359-370]. In this paper, we supply further evidence from a series of 18 patients with acquired language disorder. Of this set, a number were observed to be impaired on tests of semantic association and word-picture matching using names of object categories (e.g. objects, animals and foods), but preserved on similar tests using names of famous people. Careful methodology was applied to match object and person-specific categories for item difficulty. The study also examined whether preservation of person-specific semantic knowledge was associated with preservation of knowledge of 'biological categories' such as fruit and vegetables and animals, or with preservation of 'token' knowledge of singular categories such as countries. The findings are discussed in the context of a variety of accounts that examine whether semantic memory has a categorical structure.

"Deep" language disorders in nonfluent progressive Aphasia: an evaluation of the "summation" account of semantic errors across language production tasks.

This study focuses on the pattern of impairments seen in a new case KT, diagnosed with nonfluent progressive aphasia (NFPA), a degenerative disorder of language production. A systematic examination of KT's performance on a wide range of language production tasks (i.e., repetition, reading, spelling, spoken and written naming) determined that both written naming and repetition were better preserved than reading, spelling-to-dictation, and spoken naming. Closer examination of error performance in both reading aloud and written production revealed evidence of "deep dyslexia" and "deep dysgraphia" that has not been documented in previous cases of NFPA, and as such the present case represents the first detailed case study of this pattern of impairment in the context of progressive aphasia. An evaluation and discussion of such deep language impairment disorders in the context of other cases of NFPA has been undertaken with reference to the summation hypothesis proposed by Hillis and Caramazza (1991, 1995). It is suggested that as a principle that holds across all language production tasks, this account can encompass patterns of deep disorders thus far reported in NFPA, although other theoretical hypotheses cannot be excluded.

Phonetic and phonological analysis of progressive speech degeneration: a case study.

In this paper we report on an adult male participant with a rare form of progressive speech degeneration. We present acoustic phonetic data on his vowel and consonant production, and describe his prosody and syllable structure. We suggest possible phonological analyses of his speech, concluding that a gestural approach to phonology best characterizes his speech production and its degeneration.

Biographical knowledge: modality-specific or modality-neutral?

A number of patients have been reported who produce more semantic information in response to faces than to names, and vice versa (e.g., Eslinger et al., 1996). It has sometimes been claimed that these patterns are consistent with the hypothesis that faces and names gain access to separate, modality-specific, biographic knowledge systems. Resolving this debate has proved somewhat difficult, however, given limitations of existing data. Not only are there relatively few patients showing these particular patterns of differentiation, but also testing has often not been sufficiently thorough to rule out alternative accounts. In this paper, we present results of two studies investigating biographical knowledge differences in neurological patients and healthy adult controls. The first study focused on two patients who appeared to access more information about famous people in response to their names than to their faces. On superficial analysis, this pattern could be seen to support the notion of modality-specific biographical knowledge systems. However, closer examination revealed that, for both cases, the findings could be explained by a difficulty in face recognition, rather than by assuming separate semantic representations for faces and names. The second study investigated the role of face and name cues in accessing biographical information in younger and older healthy adults. We found that accuracy in retrieval of biographical information was significantly better with name cues for both groups. Results from these studies not only highlight the processes that must be examined in order to demonstrate modality-specific differences conclusively, but also reveal a fundamental bias in retrieval of biographical knowledge that has not been addressed in research of this nature.

Evidence for the involvement of a nonlexical route in the repetition of familiar words: A comparison of single and dual route models of auditory repetition.

In this paper, we attempt to simulate the picture naming and auditory repetition performance of two patients reported by Hanley, Kay, and Edwards (2002), who were matched for picture naming score but who differed significantly in their ability to repeat familiar words. In Experiment 1, we demonstrate that the model of naming and repetition put forward by Foygel and Dell (2000) is better able to accommodate this pattern of performance than the model put forward by Dell, Schwartz, Martin, Saffran, and Gagnon (1997). Nevertheless, Foygel and Dell's model underpredicted the repetition performance of both patients. In Experiment 2, we attempt to simulate their performance using a new dual route model of repetition in which Foygel and Dell's model is augmented by an additional nonlexical repetition pathway. The new model provided a more accurate fit to the real-word repetition performance of both patients. It is argued that the results provide support for dual route models of auditory repetition.

Anomia for common names and geographical names with preserved retrieval of names of people: a semantic memory disorder.

This paper describes the case of an anomic patient (FH) who is impaired at naming pictures of objects but has no difficulties in recalling the names of familiar people. Even though his performance on McKenna's (1997) Category Specific Naming Test was at the first percentile, he consistently recalled the names of familiar people as successfully as controls. It is argued that the pattern of performance displayed by FH represents a much clearer double dissociation with proper name anomia than any case previously reported (Cipolotti et al., 1993; Semenza and Sgaramella, 1993). FH is unable to provide detailed semantic information about many of the objects that he cannot name, even though he can recall semantic information about familiar people. Consequently his case appears to represent the mirror image of the proper name anomic patient (APA) described by Miceli et al. (2000) who was unable to recall detailed semantic information about many of the people she was unable to name. Further investigation of FH's anomia revealed impairments in retrieving both common nouns and verbs, and difficulties in retrieving and comprehending geographical names. It is argued that FH's preserved ability to name and recall biographical information about people supports the view that knowledge about familiar people may be subserved by its own dedicated neural subsystem (Kay and Hanley, 1999; Miceli et al., 2000; Gentileschi et al., 2001).

Preservation of memory for people in semantic memory disorder: Further category-specific semantic dissociation.

ML, a 70-year-old right-handed woman, presented with a history of semantic memory difficulties and a profound anomia affecting both proper nouns and common nouns following a left-hemisphere CVA some years earlier. She was found to show a striking contrast between her ability to make fine-grained semantic distinctions between objects and animals, on the one hand, and famous faces and names, on the other. Although she was impaired on a series of picture and word semantic comprehension tests when the stimuli consisted of exemplars of object and animal categories, her performance was intact when the materials comprised famous faces and names, suggesting a dissociation between the representation of person-specific knowledge and other categories of semantic information. A number of cases have been reported in which person-specific knowledge has been selectively impaired, but we would suggest that our case provides the clearest evidence so far of the reverse dissociation, in which person-specific knowledge is selectively preserved. We speculate on possible differences in the ways in which person-specific knowledge may be represented, relative to information about objects and animals.

Imageability effects, phonological errors, and the relationship between auditory repetition and picture naming: Implications for models of auditory repetition.

Hanley and Kay (1997) reported the case of a patient (PS) who showed effects of imageability on tests of auditory repetition, but whose errors were phonological rather than semantic. They argued that this pattern of performance could be explained in terms of a partial impairment to both lexical and nonlexical repetition routes so long as some interaction between the two routes was allowed, consistent with Hillis and Caramazza's (1991) "summation" hypothesis. The present paper investigates the performance of a new patient (MF) who also makes a large number of phonological errors when repeating words of low imageability. MF performs at a similar level to PS on tests of picture naming, but is less impaired than PS when repeating words and nonwords. It is argued that the pattern of performance that MF demonstrates on these and on a wide range of other tests of word production and comprehension can be readily accommodated in terms of the dual-route account of impaired auditory repetition that Hanley and Kay (1997) put forward. However, we argue that it is difficult to explain these patients' performance in terms of models of auditory word repetition that do not incorporate a separate nonlexical repetition route (Dell, Schwartz, Martin, Saffran, & Gagnon, 1997; Foygel & Dell, 2000).

An evaluation of statistical procedures for comparing an individual's performance with that of a group of controls.

The single case methodology that is widely used in cognitive neuropsychology often requires a comparison of data from a single individual (the patient) with that from a group of controls, in order to ascertain whether the patient's mean score can be viewed as significantly different from that of controls. This article reviews methods that have been used to deal with such data. Although Analysis of Variance (ANOVA) provides one possible solution of comparing group means, unequal group sizes and differences in variability between patient and controls can violate the assumptions of the test. Using Monte Carlo simulations, it was found that differences in group size and a group of N = 1 did not significantly affect the reliability of the analysis. In contrast, unacceptably high Type I errors were obtained when, in addition to unequal group sizes, there were relatively modest differences between the variance of the patient and that of the controls. We suggest that ANOVA can be used for the comparison of the mean score of an individual with that of a group of controls, but that when there is a difference in variability between the two groups, revised F criteria should be used in order to make the analysis reliable. A table of modified F values is given, which can be used for various departures from homogeneity of variance.