Investigating instances where lexical selection fails can lead to deeper insights into the cognitive machinery and architecture supporting successful word retrieval and speech production. In this paper, we used a multiplex lexical network approach that combines semantic and phonological similarities among words to model the structure of the mental lexicon. Network measures at different levels of analysis (degree, network distance, and closeness centrality) were used to investigate the influence of network structure on picture naming accuracy and errors by people with (...) Anomic, Broca's, Conduction, and Wernicke's aphasia. Our results reveal that word retrieval is influenced by the multiplex lexical network structure in at least two ways—(a) the accuracy of production and error type on incorrect productions were influenced by the degree and closeness centrality of the target word, and (b) error type also varied in terms of network distance between the target word and produced error word. Taken together, the analyses demonstrate that network science techniques, particularly the use of the multiplex lexical network to simultaneously represent semantic and phonological relationships among words, reveal how the structure of the mental lexicon influences language processes beyond traditionally examined psycholinguistic variables. We propose a framework for how the multiplex lexical network approach allows for understanding the influence of mental lexicon structure on word retrieval processes, with an eye toward a better understanding of the nature of clinical impairments, like aphasia. (shrink)

Background: Neurotypical young adults show task-based modulation and stability of their eye movements across tasks. This study aimed to determine whether persons with aphasia (PWA) modulate their eye movements and show stability across tasks similarly to control participants. Methods: Forty-eight PWA and age-matched control participants completed four eye-tracking tasks: scene search, scene memorization, text-reading, and pseudo-reading. Results: Main effects of task emerged for mean fixation duration, saccade amplitude, and standard deviations of each, demonstrating task-based modulation of eye movements. Group (...) by task interactions indicated that PWA produced shorter fixations relative to controls. This effect was most pronounced for scene memorization and for individuals who recently suffered a stroke. PWA produced longer fixations, shorter saccades, and less variable eye movements in reading tasks compared to controls. Three-way interactions of group, aphasia subtype, and task also emerged. Text-reading and scene memorization were particularly effective at distinguishing aphasia subtype. Persons with anomic aphasia showed a reduction in reading saccade amplitudes relative to their respective control group and other PWA. Persons with conduction/Wernicke’s aphasia produced shorter scene memorization fixations relative to controls or PWA of other subtypes, suggesting a memorization specific effect. Positive correlations across most tasks emerged for fixation duration and did not significantly differ between controls and PWA. Conclusions: PWA generally produced shorter fixations and smaller saccades relative to controls particularly in scene memorization and text-reading respectively. The effect was most pronounced recently after a stroke. Selectively in reading tasks, PWA produced longer fixations and shorter saccades relative to controls, consistent with reading difficulty. PWA showed task-based modulation of eye movements, though the pattern of results was somewhat abnormal relative to controls. All subtypes of PWA also demonstrated task-based modulation of eye movements. However, persons with anomic aphasia showed reduced modulation of saccade amplitude and smaller reading saccades, possibly to improve reading comprehension. Controls and PWA generally produced stabile fixation durations across tasks and did not differ in their relationship across tasks. Overall, these results suggest there is potential to differentiate among PWA with varying subtypes and from controls using eye movement measures of task-based modulation, especially reading and scene memorization tasks. (shrink)

Riassunto: Al centro di questo lavoro è l’analisi di due disturbi acquisiti del linguaggio: l’afasia di Broca e l’afasia di Wernicke. Tradizionalmente, tali disturbi sono stati interpretati come deficit che colpiscono le funzioni legate, rispettivamente, alla produzione articolatoria e alla comprensione del parlato in seguito a lesioni in due specifiche regioni cerebrali: nel caso dell’afasia di Broca, la terza circonvoluzione frontale sinistra; nel caso dell’afasia di Wernicke, la porzione posteriore del giro temporale superiore sinistro. Per tale ragione, queste due regioni (...) cerebrali, a cui ci si riferisce anche nei termini di area di Broca e area di Wernicke, sono state considerate le sedi neuroanatomiche della produzione e comprensione del linguaggio. Questo articolo mostra che, alla luce delle ricerche condotte negli ultimi decenni: non è più possibile sul piano dei deficit linguistici continuare a considerare l’afasia di Broca e l’afasia di Wernicke come disturbi unitari; non è più possibile continuare a sostenere l’esclusiva localizzazione delle funzioni di produzione e comprensione del linguaggio nelle due regioni cerebrali ad esse classicamente associate. Parole chiave: Afasia di Broca; Afasia di Wernicke; Area di Broca; Area di Wernicke; Disturbi del linguaggio; Localizzazione cerebrale; Neuroscienze Broca’s and Wernicke’s Aphasias in the Light of Contemporary Neuroscience: This paper analyzes two acquired language disorders: Broca’s aphasia and Wernicke’s aphasia. It has been commonly suggested that these disorders respectively affect functions related to speech production and language comprehension and they have been understood to result from two specific types of brain lesions: Broca’s aphasia from lesions in the third left frontal convolution; Wernicke’s aphasia from lesions in the posterior section of the left superior temporal gyrus. For this reason, these cerebral regions, also known as Broca’s area and Wernicke’s area, have long been viewed as the neuroanatomical correlates of language production and comprehension. This paper shows that in light of current research: with regard to language disorders, it is no longer possible to conceive of Broca’s and Wernicke's aphasias as unitary disorders; with regard to the cerebral localization of linguistic functions, it no longer possible to suggest that Broca’s and Wernicke’s areas are the only regions involved in speech production and comprehension. Keywords: Broca’s Aphasia; Wernicke’s Aphasia; Broca’s Area; Wernicke’s Area; Language Impairments; Cerebral Localization; Neuroscience. (shrink)

Many philosophers and psychologists have sought to explain experiences of auditory verbal hallucinations and “inserted thoughts” in schizophrenia in terms of a failure on the part of patients to appropriately monitor their own inner speech. These self-monitoring accounts have recently been challenged by some who argue that AVHs are better explained in terms of the spontaneous activation of auditory-verbal representations. This paper defends two kinds of self-monitoring approach against the spontaneous activation account. The defense requires first making some important clarifications (...) concerning what is at issue in the dispute between the two forms of theory. A popular but problematic self-monitoring theory is then contrasted with two more plausible conceptions of what the relevant self-monitoring deficits involve. The first appeals to deficits in the neural mechanisms that normally filter or attenuate sensory signals that are the result of one’s own actions. The second, less familiar, form of self-monitoring approach draws an important analogy between Wernicke’s aphasia and AVHs in schizophrenia. This style of self-monitoring theory pursues possible connections among AVHs, inserted thoughts, and the disorganized speech characteristic formal thought disorder. (shrink)

The species-specific organizational property of speech is a continual mouth open-close alternation, the two phases of which are subject to continual articulatory modulation. The cycle constitutes the syllable, and the open and closed phases are segments framescontent displays that are prominent in many nonhuman primates. The new role of Broca's area and its surround in human vocal communication may have derived from its evolutionary history as the main cortical center for the control of ingestive processes. The frame and content components (...) of speech may have subsequently evolved separate realizations within two general purpose primate motor control systems: (1) a motivation-related medial system, including anterior cingulate cortex and the supplementary motor area, for self-generated behavior, formerly responsible for ancestral vocalization control and now also responsible for frames, and (2) a lateral system, including Broca's area and surround, and Wernicke's area, specialized for response to external input (and therefore the emergent vocal learning capacity) and more responsible for content. (shrink)

Psychoanalysis is often divided into two parts: the clinical theory and the metapsychology. Recent historical and philosophical work has led some psychoanalysts to argue that the metapsychology is a cryptic biology and not a psychological theory at all. Evidence for this view is largely that metapsychological concepts can be traced to Freud's "Project for a Scientific Psychology", in which he seems to argue that systems of neurons perform both psychological and neuro-physiological functions. The conclusion these writers have drawn is that (...) Freud's metapsychology represents an attempt to unify two putatively incommensurable conceptual frameworks: the psychological and the physiological. ;In the first chapter I review the dispute between Wernicke and Freud on the issue of aphasia and place it in the context of 19th century psychological explanatory traditions. One of these traditions, developed by Franz Joseph Gall, predominates in Wernicke's work. The other tradition, associationism as developed by John Stuart Mill and Alexander Bain, predominates in Freud's critique of Wernicke. I suggest that Wernicke's cerebral localization strategy amounts to a type-type identity theory, and that Freud presented both empirical and conceptual reasons for rejecting this commitment. ;In the second chapter I explicate Freud's "Project" and chapter VII of The Interpretation of Dreams. In the latter, I argue, Freud develops a version of functionalism. His break with his neurological background is exemplified by his insistence that psychology is autonomous. ;In the third chapter I evaluate critically the arguments presented by Merton Gill, George Klein, and Roy Schaffer that purport to show Freud's metapsychology is not a psychology at all, but a neuro-biology. Against this view I suggest that Freud describes mental structures that serve various design functions. These structures, attributed to persons by the metapsychology of infantile wishes and regression, are cognitively impenetiable. The notion that the design or functional architecture of a system is cognitively impenetiable is used to account for the protracted nature, perhaps interminability, of psychoanalytic therapy. Freud's therapeutic pessimism has its roots in theory rather than therapeutic failure. (shrink)

The first major advances in the understanding of the neurological bases for language abilities were the results of the study of the brains and behaviors of patients with language impairments due to focal brain damage. The two most prominent pioneers in this field are remembered because their names have become associated with distinctive aphasia (language loss) syndromes and the brain regions associated with them. In 1861 Paul Broca described the damage site in the brain of a patient who had (...) lost the ability to produce articulate speech as a result of a stroke. Broca's aphasia, as it is now commonly called, is produced by damage that involves the inferior left frontal lobe of the brain. It tends to produce both a loss of articulatory skill (sometimes but not always with paralysis) and (as discovered much later) problems with grammar and syntax, including grammatical comprehension under certain conditions. Despite speech production impairments, Broca's aphasics do not have basic word‐ and sentence‐comprehension difficulties, when comprehension is not dependent on syntactic analysis. In 1874 Carl Wernicke demonstrated that damage to the left superior temporal lobe produced a different syndrome of language impairments. Wernicke's aphasia generally spares fluent, syntactic speech but impairs the use and comprehension of content words. Wernicke's aphasics'speech includes inappropriate word substitutions, neologisms, and semantic confusions, and their comprehension is similarly disturbed. These early studies also demonstrated that these aphasic disturbances were almost exclusively associated with damage to the structures of the left cerebral hemisphere, even though anatomically corresponding structures are present on both sides of the brain. However, this is not true of all language functions. Some left‐handed individuals can suffer aphasia from right hemisphere damage, and recent studies of patients with right hemisphere damage without aphasia have demonstrated impairment of their comprehension above the sentence level (e.g., interpretation of jokes and stories) and in the production and interpretation of prosodic features of speech (rhythmic and tonal patterning that conveys emphasis and emotion). (shrink)

This book offers an exciting re-interpretation of Auguste Comte, the founder of French sociology. Following the development of his philosophy of positivism, Comte later focused on the importance of the emotions in his philosophy resulting in the creation of a new religious system, the Religion of Humanity. Andrew Wernick provides the first in-depth critique of Comte's concept of religion and its place in his thinking on politics, sociology and philosophy of science. He places Comte's ideas in the context of post-1789 (...) French political and intellectual history, and of modern philosophy, especially postmodernism. Wernick relates Comte to Marx and Nietzsche as seminal figures of modernity and examines key features of modern and postmodern French social theory, tracing the inherent flaws and disintegration of Comte's system. Wernick offers original and fascinating insights in this rich study which will attract a wide audience from sociologists and philosophers to cultural theorists and historians. (shrink)

Three types of problems are raised in this commentary: On the linguistic side, we emphasize the importance of an appropriate definition of the different domains of linguistics. This is needed to define the domains (lexicon-syntax-semantics) to which transformational relations apply. We then question the concept of Broca's aphasia as a “functional” syndrome, associated with a specific lesion. Finally, we discuss evidence from functional brain imaging. The breadth and potential impact of such evidence has grown considerably in the last few (...) years, expanding our knowledge of the multiple contributions of the “Broca's region” to phonological, lexical-semantic, and syntactic processing. “Lumping” under diagnostic labels, such as Broca's aphasia, should be replaced by more detailed linguistic and neurological descriptions of the clinical cases. (shrink)

Activism undertaken by CEOs has been on the rise in recent years. Research on this practice has been primarily concerned with determining the conditions under which a CEO’s public statements on sociopolitical issues are beneficial or detrimental to her firm’s business performance. We complement this instrumental perspective on CEO activism with an ethical investigation of the implications of CEO activism for the democratic process. Drawing on political philosophy, we show that the answer to the question of whether CEO activism is (...) conducive to the democratic process depends on the view of democracy that is adopted. From the perspective of liberalism, the sole requirement that an instance of CEO activism must fulfill is that it is lawful, provided that the applicable law sufficiently protects people’s essential rights. However, from the viewpoint of republicanism, this is not a sufficient condition. Besides being law-abiding, CEOs should be “civic-minded” when intervening in public debates, i.e., concerned with the quality and fairness with which those debates are conducted. Based on the literature on republicanism, we suggest four possible criteria that civic-minded CEOs can apply to gauge the democratic conduciveness of a possible public intervention: added insight, timeliness, constructiveness, and transparency. Our article complements the predominantly instrumentally oriented literature on CEO activism and contributes, more broadly, to the literature that explores the normative dimensions of corporate political involvement, as well as to a growing strand of research that draws on philosophical theory to inform business leaders’ ethical decision-making. (shrink)

The university is an archaic institution and can claim to have a more or less continuous history over more than two millennia and, at least in the forms that prevail today, could be regarded as a ‘Western’ institution. However, the combination of globalization and cybernation will set the parameters for the next round of the university's development. A trend will be the growth of global universities, both virtual and land-based. At the same time, the growth of professional life outside of (...) and between institutions has lessened dependency on them, and the academic intelligentsia has become interconnected as never before. (shrink)

Against the current background of renewed publisher interests in encyclopedias, the article examines the modern genealogy of the Encyclopedia project. The article focuses particularly on three moments: Bacon’s ‘Great Instauration’ and attempted fashioning of a ‘New Organon’ (as against the old one of Aristotle), the Encylopedia of 1751 and its revolutionary-era successors, and Comte’s ‘system’ of positive philosophy. D’Alembert and Diderot’s classificatory tree, with its secularized capture of moral and political philosophy, was an attempt to improve on Bacon. Comte’s grand (...) systematizing was an attempt to cap their efforts by being entirely ‘positive’. For this, a science of society and a social standpoint were essential. His effort to fulfill Bacon’s totalizing dream of fully scientific (re-)systematization of knowledge, was a heroic and perhaps absurd failure. But, the article argues, Comte’s critique of Diderot and d’Alembert, with respect to what he took to be the radical incoherence of their classificatory ‘tree’ of knowledge, and his more general critique of both Bacon and 18th-century ‘encyclopedism’ for holding out the possibility of an objective (as opposed to subjective, and human-centered) synthesis of knowledge, touch on ‘metaphysical’ features of the epistemic landscape that, in new forms, are still with us. Comte’s forthright (and sociologically reflexive) articulation of the technocratic and religious dimensions of the Baconian project also illuminates elements of the (French) Enlightenment and derivatives from it that have not received sufficient attention, particularly in relation to one another. (shrink)

The article offers a critical but sympathetic reflection on the development of classical and post-classical French sociology. From Comte onwards, I suggest, the modern French treatment of the social has been preoccupied with socio-theological questions; and even with the radical deconstruction of any society-god, this continues to be the case. There are distinctive historical reasons for this (including the Catholic inheritance and an enduring legitimacy problem for the Republican state); but the significance of the issues raised by this intellectual tradition (...) as a result goes beyond the limits of national context. In an age of post-histoire and the `death' of everything, the `French' travails of social ontology, including the quasi-religious register in which these have occurred, have deep and continuing import for any would-be progressive social theory as such. We need to rethink the `we'. With such considerations in mind, the body of the article considers Comte's concept of Humanity and Baudrillard's `end of the social' as exemplifying key aspects of the beginning (reconstructive) and ending (deconstructive) phases of the French sociological story. What began as a detour in the `death of God', I argue, has terminated in a `second death of God' in which a replacement divinity and the rationalist faith associated with it have disintegrated and become impossible to think. But the logic of this development has not been straightforward. It is marked by a double paradox. An interrogation of Comte's `Humanity' reveals it to be a semi-conscious exercise in simulation, haunted by the implications of its own emptiness. On the one hand, then, the attempted religious founding founded nothing (it made a transcendent of its own intended re-socializing effects). On the other hand, as exemplified by Baudrillard's pronouncements about the end of the social, the moment of disintegration has itself seemed to offer a new socio-theological opening. Rather than mourn the anomic or hyper-real impossibility of a transcending `we', Baudrillard would shift terrain in a quasi-Nietzschean (or Bataillian) transvaluation. This implies (against Baudrillard himself) not the definitive end of the French `sociological' project, but the possibility of its continuation, albeit under erasure and in a new key. (shrink)

This commentary focuses on the larger implications of Grodzinsky's hypothesis. Although Grodzinsky argues persuasively that the syntactic comprehension deficits in Broca's aphasia involve mainly an inability to comprehend sentences requiring a transformational movement of phrasal constituents, his larger claim for a distinct and dedicated “language organ” in the left hemisphere is much less tenable.

The argument that Broca's area is preferentially involved in specific syntactic operations is based on a strong assertion regarding patterns of sentence comprehension found among patients with Broca's aphasia. This assertion is shown to be largely inconsistent with the available evidence from published studies, which indicates that only a subgroup of Broca patients demonstrate the target pattern.

We agree with MacNeilage's claim that speech stems from a volitional vocalization pathway between the cingulate and the supplementary motor area (SMA). We add the vocal self- monitoring system as the first recruitment of the Broca-Wernicke circuit. SMA control for “frames” is supported by wrong consonant-vowel recurring utterance aphasia and an imaging study of quasi-reiterant speech. The role of Broca's area is questioned in the emergence of “content,” because a primary motor mapping, embodying peripheral constraints, seems sufficient. Finally, we (...) reject a uniquely peripheral account of speech emergence. (shrink)

Many authors assume that Broca's area subserves the functions that are lost in patients with Broca's aphasia. This commentary attempts to clarify the relationship between Broca's area and Broca's aphasia and suggests that statements about the neurology of patients' specific language functions might be better supported by their individual structural neuroimaging data.

I begin with a characterization of neurolinguistic theories, trying to pinpoint some general properties that an account of brain/language relations should have. I then address specific criticisms made in the commentaries regarding the syntactic theory assumed in the target article, properties of the Trace Deletion Hypothesis (TDH) and the Tree-Pruning Hyothesis (TPH), other experimental results from aphasia, and findings from functional neuroimaging. Despite the criticism, the picture of the limited role of Broca's area remains unchanged.

Grodzinsky proposes that agrammatism leads to a “pruning” of the syntactic tree in speech production. For German, this assumption predicts that syntactic processes related to functional projections AgrP and CP should be impaired. An analysis of spontaneous-speech data from four Broca's aphasics with respect to subject-verb agreement and verb placement, however, indicates that phrase-structure representations in agrammatism are intact.

The comprehension problem in Broca's patients does not stem from an inability to represent argument traces. There can be good comprehension in the presence of (object) traces and impaired comprehension can result in constructions where there are no (object) argument traces. This leads to an alternative understanding of Broca's comprehension, one that places the locus of the impairment in an inability to construct syntactic representation on time.

I wholeheartedly endorse Grodzinsky's program of attempting to tie the particular deficits observed in Broca's aphasics' comprehension and production to changes in their mentally represented model of grammar. At the level of detail, however, I see problems with two specific changes that Grodzinsky posits. One is a default Agent-assignment strategy in comprehension. The other is the hypothesis that production involves pruning all functional projections above Agreement Phrase.

Logopenic variant primary progressive aphasia is a neurodegenerative language disorder primarily characterized by impaired phonological processing. Sentence repetition and comprehension deficits are observed in lvPPA and linked to impaired phonological working memory, but recent evidence also implicates impaired speech perception. Currently, neural encoding of the speech envelope, which forms the scaffolding for perception, is not clearly understood in lvPPA. We leveraged recent analytical advances in electrophysiology to examine speech envelope encoding in lvPPA. We assessed cortical tracking of the speech (...) envelope and in-task comprehension of two spoken narratives in individuals with lvPPA and age-matched controls. Despite markedly reduced narrative comprehension relative to controls, individuals with lvPPA had increased cortical tracking of the speech envelope in theta oscillations, which track low-level features, but not delta oscillations, which track speech units that unfold across a longer time scale. This neural signature was highly correlated across narratives. Results indicate an increased reliance on acoustic cues during speech encoding. This may reflect inefficient encoding of bottom-up speech cues, likely as a consequence of dysfunctional temporoparietal cortex. (shrink)

To what extent is the neural organization of language dependent on factors specific to the modalities in which language is perceived and through which it is produced? That is, is the left-hemisphere dominance for language a function of a linguistic specialization or a function of some domain-general specialization(s), such as temporal processing or motor planning? Investigations of the neurobiology of signed language can help answer these questions. As with spoken languages, signed languages of the deaf display complex grammatical structure but (...) are perceived and produced via radically different modalities. Thus, by mapping out the neurological similarities and differences between signed and spoken language, it is possible to identify modality-specific contributions to brain organization for language. Research to date has shown a significant degree of similarity in the neurobiology of signed and spoken languages, suggesting that the neural organization of language is largely modality-independent. (shrink)

This article examines Nietzsche’s evaluations of silence and laughter as Pyrrho’s two responses to the dilemma caused by doubts about truth in aphorism 213 of ‘The Wanderer and His Shadow’ (WS 213). Contrary to the common belief that speechlessness leads Pyrrho to tranquillity (ataraxia), in WS 213, it is a symptom of his intellectual impotence caused by logical impasse. Silence proves to be subject to the same traps as speeches. In his later period, Nietzsche deems Pyrrho’s impotent will to truth (...) and pursuit of tranquility nihilism. He contends that Pyrrho’s impotence triggers his ressentiment of dogmatists and labels Pyrrho as a Greek Buddhist in unpublished sections writtenin 1888. For Nietzsche, the only antidote to dogmatism and even nihilism is laughter, a way of overcoming Pyrrho’s obstinate will to truth embodied in the form of logical argumentation. Nietzsche seems to attribute the Democritean cheerfulness (euthumia) to Pyrrho, a manifestation of healthy skepticism and a dynamicconstellation of drives that embrace and overcome suffering. In Thus Spoke Zarathustra, Nietzsche claims that laughter is a sign of recovery from a spirit of excessive seriousness, which is embodied by the free-spirited Zarathustra, an antipode to Pyrrho ‘the fanatic of mistrust.’. (shrink)

This article examines Nietzsche’s evaluations of silence and laughter as Pyrrho’s two responses to the dilemma caused by doubts about truth in aphorism 213 of ‘The Wanderer and His Shadow’ (WS 213). Contrary to the common belief that speechlessness leads Pyrrho to tranquillity (ataraxia), in WS 213, it is a symptom of his intellectual impotence caused by logical impasse. Silence proves to be subject to the same traps as speeches. In his later period, Nietzsche deems Pyrrho’s impotent will to truth (...) and pursuit of tranquility nihilism. He contends that Pyrrho’s impotence triggers his ressentiment of dogmatists and labels Pyrrho as a Greek Buddhist in unpublished sections writtenin 1888. For Nietzsche, the only antidote to dogmatism and even nihilism is laughter, a way of overcoming Pyrrho’s obstinate will to truth embodied in the form of logical argumentation. Nietzsche seems to attribute the Democritean cheerfulness (euthumia) to Pyrrho, a manifestation of healthy skepticism and a dynamicconstellation of drives that embrace and overcome suffering. In Thus Spoke Zarathustra, Nietzsche claims that laughter is a sign of recovery from a spirit of excessive seriousness, which is embodied by the free-spirited Zarathustra, an antipode to Pyrrho ‘the fanatic of mistrust.’. (shrink)

Our objective is to corroborate Merleau-Ponty's phenomenology of speech perception and intersubjectivity through an analysis of A. R. Luria's account of semantic aphasia. By emulating Merleau-Ponty's style of analysis in dealing with the work of a contemporary leader in the field of aphasiology, we are able to take up Merleau-Ponty's thought and test whether his conclusions are inevitable or whether they are based on outmoded problems of the psychology and psychopathology of his day. These reflections also enable us to (...) present arguments against both the assumptions of the natural attitude, as well as those of transcendental phenomenology, and so enable us to cast some light on the relation between existential phenomenology and empirical research. By contrasting aphasic and normal perception, we intend to show that ultimately even the aphasiologist is able to characterize aphasic perception only in terms of the aphasic's loss of an "openness" to meanings present in the uttered sounds. We argue that this notion of openness, like that of Merleau-Ponty's notion of "perceptual faith, " requires the reduction but also points to the impossibility of a complete reduction. (shrink)

Primary progressive aphasia is a clinical syndrome in which patients progressively lose speech and language abilities. Three variants are recognized: logopenic, associated with phonology and/or short-term verbal memory deficits accompanied by left temporo-parietal atrophy; semantic, associated with semantic deficits and anterior temporal lobe atrophy; non-fluent associated with grammar and/or speech-motor deficits and inferior frontal gyrus atrophy. Here, we set out to investigate whether the three variants of PPA can be dissociated based on error patterns in a single language task. (...) We recruited 21 lvPPA, 28 svPPA, and 24 nfvPPA patients, together with 31 healthy controls, and analyzed their performance on an auditory noun-to-verb generation task, which requires auditory analysis of the input, access to and selection of relevant lexical and semantic knowledge, as well as preparation and execution of speech. Task accuracy differed across the three variants and controls, with lvPPA and nfvPPA having the lowest and highest accuracy, respectively. Critically, machine learning analysis of the different error types yielded above-chance classification of patients into their corresponding group. An analysis of the error types revealed clear variant-specific effects: lvPPA patients produced the highest percentage of “not-a-verb” responses and the highest number of semantically related nouns ; in contrast, svPPA patients produced the highest percentage of “unrelated verb” responses and the highest number of light verbs. Taken together, our findings indicate that error patterns in an auditory verb generation task are associated with the breakdown of different neurocognitive mechanisms across PPA variants. Specifically, they corroborate the link between temporo-parietal regions with lexical processing, as well as ATL with semantic processes. These findings illustrate how the analysis of pattern of responses can help PPA phenotyping and heighten diagnostic sensitivity, while providing insights on the neural correlates of different components of language. (shrink)

Background and Purpose The decision to perform decompressive craniectomy for patients with malignant MCA syndrome can be ethically complex. We investigated factors that clinicians consider in this decision-making process. Methods A survey including clinical vignettes and attitudes questions surrounding the use of hemicraniectomy in malignant MCA syndrome was distributed to 203 neurosurgeons, neurologists, staff and residents, and nurses and allied health members specializing in the care of neurological patients. These were practicing health care providers situated in an urban setting in (...) Canada where access to health care is covered by national policy and is a human right. Results Eighty-eight participants responded to survey. All participants unanimously supported the procedure for young and healthy patients. Advanced age, the presence of aphasia, comorbid medical conditions, and poor baseline functional status were dominant factors associated with increasing reluctance to offer surgical decompression. Patients’ previously expressed wishes were also an important consideration. Eighty-six percent of respondents agreed that withholding surgery is ethically justified if the outcome is perceived as futile. Conclusions Health care providers use similar factors to determine if aggressive management is justified given anticipated burden on patient quality of life and extended impact on society. This convergence can be harnessed beneficially for the transparent communication of medical options in the ethically complex setting of decompressive hemicraniectomy post-stroke. (shrink)