Kinesiophobia and symptomatology in chronic fatigue syndrome: A psychometric study of two questionnaires

Objectives. The aims of the study were to examine the reliability of the Dutch and French versions of the Tampa scale kinesiophobia (TSK) version chronic fatigue syndrome (CFS), and to examine the reliability and validity of the Dutch and French versions of the CFS symptom list. Design. Repeated‐measures design. Methods. Native Dutch speakers (N=100) and native French (N=48) speakers fulfilling the diagnostic criteria for CFS were asked to list the five most important symptoms and to complete the TSK–CFS, the CFS symptom list, and the Short Form 36 Health Status Survey or SF‐36. A modified version of the TSK–CFS and the CFS symptom list was filled in within 24 hours of the first assessment. Results. The French and Dutch version of the TSK–CFS and CFS symptom lists displayed good reliability (ICC≥.83). The CFS symptom list was internally consistent (Cronbach's α≥.93) and concurrently valid with the SF‐36. For the native Dutch and French speakers, respectively, 82 and 78% of the self‐reported symptoms matched the content of CFS symptom list. Conclusions. The results are in support of the psychometric properties of the French and Dutch versions of both the TSK–CFS and the CFS symptom list for assessing kinesiophobia and symptom severity, respectively.     

Toward a brain-based componential semantic representation

ABSTRACT

Componential theories of lexical semantics assume that concepts can be represented by sets of features or attributes that are in some sense primitive or basic components of meaning. The binary features used in classical category and prototype theories are problematic in that these features are themselves complex concepts, leaving open the question of what constitutes a primitive feature. The present availability of brain imaging tools has enhanced interest in how concepts are represented in brains, and accumulating evidence supports the claim that these representations are at least partly “embodied” in the perception, action, and other modal neural systems through which concepts are experienced. In this study we explore the possibility of devising a componential model of semantic representation based entirely on such functional divisions in the human brain. We propose a basic set of approximately 65 experiential attributes based on neurobiological considerations, comprising sensory, motor, spatial, temporal, affective, social, and cognitive experiences. We provide normative data on the salience of each attribute for a large set of English nouns, verbs, and adjectives, and show how these attribute vectors distinguish a priori conceptual categories and capture semantic similarity. Robust quantitative differences between concrete object categories were observed across a large number of attribute dimensions. A within- versus between-category similarity metric showed much greater separation between categories than representations derived from distributional (latent semantic) analysis of text. Cluster analyses were used to explore the similarity structure in the data independent of a priori labels, revealing several novel category distinctions. We discuss how such a representation might deal with various longstanding problems in semantic theory, such as feature selection and weighting, representation of abstract concepts, effects of context on semantic retrieval, and conceptual combination. In contrast to componential models based on verbal features, the proposed representation systematically relates semantic content to large-scale brain networks and biologically plausible accounts of concept acquisition.     

Object category structure in response patterns of neuronal population in monkey inferior temporal cortex

Our mental representation of object categories is hierarchically organized, and our rapid and seemingly effortless categorization ability is crucial for our daily behavior. Here, we examine responses of a large number (>600) of neurons in monkey inferior temporal (IT) cortex with a large number (>1,000) of natural and artificial object images. During the recordings, the monkeys performed a passive fixation task. We found that the categorical structure of objects is represented by the pattern of activity distributed over the cell population. Animate and inanimate objects created distinguishable clusters in the population code. The global category of animate objects was divided into bodies, hands, and faces. Faces were divided into primate and nonprimate faces, and the primate-face group was divided into human and monkey faces. Bodies of human, birds, and four-limb animals clustered together, whereas lower animals such as fish, reptile, and insects made another cluster. Thus the cluster analysis showed that IT population responses reconstruct a large part of our intuitive category structure, including the global division into animate and inanimate objects, and further hierarchical subdivisions of animate objects. The representation of categories was distributed in several respects, e.g., the similarity of response patterns to stimuli within a category was maintained by both the cells that maximally responded to the category and the cells that responded weakly to the category. These results advance our understanding of the nature of the IT neural code, suggesting an inherently categorical representation that comprises a range of categories including the amply investigated face category.     

Grammatical category dissociation in multilingual aphasia

Word retrieval deficits for specific grammatical categories, such as verbs versus nouns, occur as a consequence of brain damage. Such deficits are informative about the nature of lexical organization in the human brain. This study examined retrieval of grammatical categories across three languages in a trilingual person with aphasia who spoke Arabic, French, and English. In order to delineate the nature of word production difficulty, comprehension was tested, and a variety of concomitant lexical–semantic variables were analysed. The patient demonstrated a consistent noun–verb dissociation in picture naming and narrative speech, with severely impaired production of verbs across all three languages. The cross-linguistically similar noun–verb dissociation, coupled with little evidence of semantic impairment, suggests that (a) the patient has a true “nonsemantic” grammatical category specific deficit, and (b) lexical organization in multilingual speakers shares grammatical class information between languages. The findings of this study contribute to our understanding of the architecture of lexical organization in bilinguals.     

Visual and visuomotor processing of hands and tools as a case study of cross talk between the dorsal and ventral streams

A major principle of organization of the visual system is between a dorsal stream that processes visuomotor information and a ventral stream that supports object recognition. Most research has focused on dissociating processing across these two streams. Here we focus on how the two streams interact. We tested neurologically-intact and impaired participants in an object categorization task over two classes of objects that depend on processing within both streams—hands and tools. We measured how unconscious processing of images from one of these categories (e.g., tools) affects the recognition of images from the other category (i.e., hands). Our findings with neurologically-intact participants demonstrated that processing an image of a hand hampers the subsequent processing of an image of a tool, and vice versa. These results were not present in apraxic patients (N?=?3). These findings suggest local and global inhibitory processes working in tandem to co-register information across the two streams.     

How do 9‐month‐old infants categorize human and ape faces? A rapid repetition ERP study

The current study investigates how infants categorize human compared to ape faces. Nine‐month‐old infants were presented with priming stimuli related to human (N = 24) or ape (N = 25) face targets on different levels of categorization. Event‐related potentials were recorded during a passive‐looking rapid repetition paradigm. In a within‐subjects design, priming effects of the same faces, different faces from the same basic‐level category, different faces from the other basic‐level category (human/ape faces), and house fronts were examined. Human and ape faces were first categorized on a superordinate level (“faces”), as indicated by enhanced P1 amplitude and reduced P1 latency for faces primed by any faces. Then, human and ape faces were categorized on a basic level. N290 amplitude and latency were larger for human and monkey targets primed by human faces. Neither human nor ape faces were categorized on the individual level.     

Controlling for interstimulus perceptual variance abolishes N170 face selectivity

Establishing when and how the human brain differentiates between object categories is key to understanding visual cognition. Event-related potential (ERP) investigations have led to the consensus that faces selectively elicit a negative wave peaking 170 ms after presentation, the 'N170'. In such experiments, however, faces are nearly always presented from a full front view, whereas other stimuli are more perceptually variable, leading to uncontrolled interstimulus perceptual variance (ISPV). Here, we compared ERPs elicited by faces, cars and butterflies while--for the first time--controlling ISPV (low or high). Surprisingly, the N170 was sensitive, not to object category, but to ISPV. In addition, we found category effects independent of ISPV 70 ms earlier than has been generally reported. These results demonstrate early ERP category effects in the visual domain, call into question the face selectivity of the N170 and establish ISPV as a critical factor to control in experiments relying on multitrial averaging.     

Categorizing natural objects: a comparison of the visual and the haptic modalities

Although the hands are the most important tool for humans to manipulate objects, only little is known about haptic processing of natural objects. Here, we selected a unique set of natural objects, namely seashells, which vary along a variety of object features, while others are shared across all stimuli. To correctly interact with objects, they have to be identified or categorized. For both processes, measuring similarities between objects is crucial. Our goal is to better understand the haptic similarity percept by comparing it to the visual similarity percept. First, direct similarity measures were analyzed using multidimensional scaling techniques to visualize the perceptual spaces of both modalities. We find that the visual and the haptic modality form almost identical perceptual spaces. Next, we performed three different categorization tasks. All tasks exhibit a highly accurate processing of complex shapes of the haptic modality. Moreover, we find that objects grouped into the same category form regions within the perceptual space. Hence, in both modalities, perceived similarity constitutes the basis for categorizing objects. Moreover, both modalities focus on shape to form categories. Taken together, our results lead to the assumption that the same cognitive processes link haptic and visual similarity perception and the resulting categorization behavior.     

Selectivity of lexical-semantic disorders in Polish-speaking patients with aphasia: Evidence from single-word comprehension

Several neuropsychological studies have shown that patients with brain damage may demonstrate selective category-specific deficits of auditory comprehension. The present paper reports on an investigation of aphasic patients’ preserved ability to perform a semantic task on spoken words despite severe impairment in auditory comprehension, as shown by failure in matching spoken words to pictured objects. Twenty-six aphasic patients (11 women and 15 men) with impaired speech comprehension due to a left-hemisphere ischaemic stroke were examined; all were right-handed and native speakers of Polish. Six narrowly defined semantic categories for which dissociations have been reported are colors, body parts, animals, food, objects (mostly tools), and means of transportation. An analysis using one-way ANOVA with repeated measures in conjunction with the Lambda-Wilks Test revealed significant discrepancies among these categories in aphasic patients, who had much more difficulty comprehending names of colors than they did comprehending names of other objects (F_(5,21) = 13.15; p < .001). Animals were most often the easiest category to understand. The possibility of a simple explanation in terms of word frequency and/or visual complexity was ruled out. Evidence from the present study support the position that so called “global” aphasia is an imprecise term and should be redefined. These results are discussed within the connectionist and modular perspectives on category-specific deficits in aphasia.     

Domain‐specific deficits in schizophrenia

Introduction.?Object recognition deficits are well documented in certain neurological disorders (e.g., Alzheimer's disease, herpes simplex encephalitis). Although agnosic problems have been documented in some patients with schizophrenia (Gabrovska et al., ), no study has investigated whether such deficits differentially affect specific categories of information (as they sometimes do in neurological cases).

Method.?In Part I of this study, we compared object recognition in 55 patients with chronic schizophrenia and 22 age‐ and NART IQ‐matched healthy controls. In Part II, we present a detailed case study of one patient with schizophrenia (DH) who displays a severe category specific semantic knowledge for living things.

Results.?Of the patients with schizophrenia, 75% had object recognition below the 5th percentile, and in 11% of cases, a highly specific classical category dissociation emerged (5 cases with nonliving deficit and 1 with living deficit); and two other patients showed strong dissociation for living things. These findings provide convincing evidence of a classical double dissociation across the two categories. In Part II, the in‐depth case study of one schizophrenic patient (DH), documented a profound agnosia for living things. While DH displayed intact low level perceptual and spatial ability and could copy drawings, he was severely impaired at naming, picture‐name matching, semantic fluency, and could not describe or draw items from memory.

Conclusions.?The presence of impaired object recognition in most schizophrenic patients, along with highly selective category specific deficits in a minority, is discussed with reference to similar findings in neurological patients.     

It's a word: early electrophysiological response to the character likeness of pictographs

Using unfamiliar and meaningless pictographs that varied in their degree of similarity to Chinese characters, the current study tested whether the early electrophysiological response was modulated by character likeness. We measured P100 and N170 while 20 native Chinese speakers were viewing Chinese characters, drawings of objects, and pictographs. Comparisons across the three categories of stimuli showed that pictographs elicited a smaller N170 amplitude than did Chinese characters and a stronger N170 amplitude than did objects, but did not differ in the P100 amplitude from the other two categories. Within the category of pictographs, stimuli with a higher degree of character likeness elicited larger N170 amplitudes and shorter N170 peak latencies, and this effect was again not observed in P100. These results suggest that N170 is sensitive to visual stimuli's character likeness even though they are unfamiliar pictographs with no meanings or sounds.     

Prior knowledge of category size impacts visual search

Prior research has shown that category search can be similar to one‐item search (as measured by the N2pc ERP marker of attentional selection) for highly familiar, smaller categories (e.g., letters and numbers) because the finite set of items in a category can be grouped into one unit to guide search. Other studies have shown that larger, more broadly defined categories (e.g., healthy food) also can elicit N2pc components during category search, but the amplitude of these components is typically attenuated. Two experiments investigated whether the perceived size of a familiar category impacts category and exemplar search. We presented participants with 16 familiar company logos: 8 from a smaller category (social media companies) and 8 from a larger category (entertainment/recreation manufacturing companies). The ERP results from Experiment 1 revealed that, in a two‐item search array, search was more efficient for the smaller category of logos compared to the larger category. In a four‐item search array (Experiment 2), where two of the four items were placeholders, search was largely similar between the category types, but there was more attentional capture by nontarget members from the same category as the target for smaller rather than larger categories. These results support a growing literature on how prior knowledge of categories affects attentional selection and capture during visual search. We discuss the implications of these findings in relation to assessing cognitive abilities across the lifespan, given that prior knowledge typically increases with age.     

N400 as an index of uncontrolled categorization processing in brand extension

This study examined the ERP (event-related potential) correlates of categorization processing in brand extension with irrelative task. Participants faced two sequential stimuli in a pair consisting of a soft drink brand name (S1) and a product name (S2) which comprised two categories: beverage (typical product of the brand, e.g. Coke branded soda water) and clothing (atypical product of the brand, even though sometimes it was seen in the real market, e.g. Coke branded sport wear). The N400 was recorded and more largely distributed in frontal, frontal–central and central areas when S2 was clothing compared with beverage. The study did not require the participants to evaluate that the brand extension was appropriate or not, the N400 recorded here was, therefore, irrelative to the task difficulty and the conscious categorization process. We speculated that it reflected an integration processing related with the mental category. The brand performed the role of prime which aroused the participants’ association of the brand-related typical products and attributes retrieving from their long term memory. The product name activated an unconscious processing of comparison between the brand and the product. In this process, the participant treated the brand as a mental category and classified the product as a member of it. There would be a large cognitive reaction which elicited the N400 if the product's attributes were atypical to the category of the brand. These findings might help us understand the N400 component in unconscious mental categorization and supported the categorization hypotheses in brand extension theory which was crucial in consumer psychology.     

The organization of the conceptual system: The case of the “object versus action” dimension

There are very numerous reports in the neuropsychological literature of patients showing, in naming and/or comprehension tasks, a disproportionate deficit for nouns in comparison with verbs or a disproportionate deficit for verbs in comparison with nouns. A number of authors advanced that, in at least some or even in every of these reported cases, the noun/verb dissociation in fact reflected an underlying conceptual deficit disproportionately affecting either object or action concepts. These patterns thus would put an additional constraint on theories of conceptual knowledge organization, which should be able to explain how brain damage could selectively disrupt the concepts of objects or the concepts of actions. We have reviewed 69 papers (published from 1984 to 2009) that reported a pattern of a noun or a verb disproportionate deficit in a single-case, multiple-case, or group study of brain-damaged patients with various aetiologies. From this review, we concluded that none of these studies provided compelling evidence in favour of the interpretation that the observed noun or verb disproportionate deficit arose at the conceptual processing level and, accordingly, that this level may be organized according to the “object/action” dimension. Furthermore, we argue that investigating conceptual impairments in brain-damaged patients according to the “object/action” dichotomy is not empirically fruitful if the purpose is to inform theories of conceptual knowledge organization. In order to provide evidence relevant to these theories, one needs to consider finer grained distinctions within both the object and the action category when investigating the scope of the patients' conceptual impairment.     

After the P3: late executive processes in stimulus categorization

Two experiments examined the hypothesis that dual systems of stimulus evaluation for categorization can be observed in event-related potentials: one whose duration is indexed by the latency of the P3 component, and a second evident in a later frontal potential. Subjects categorized artificial animals by a "two out of three" rule. Stimuli with two visual features of their own category and one feature of a different category (i.e., near the boundary between categories) elicited very prolonged reaction times as compared to stimuli with three features from a single category. This response time (RT) delay was not accompanied by a delayed P3, suggesting that the P3 indexed only a first pass of stimulus evaluation. The near-boundary stimuli elicited more positive potentials than far-boundary stimuli at prefrontal and frontotemporal sites, suggesting that a secondary stage of stimulus evaluation was triggered when detection of single features or simple conjunctions was insufficient to support a correct decision. The frontal potential that was sensitive to categorization difficulty was of opposite polarity to frontal potentials previously observed in manipulations of working memory. The roles of frontal executive processes in categorization and memory tasks are discussed.     

N1 response attenuation and the mismatch negativity (MMN) to within‐ and across‐category phonetic contrasts

According to the neural adaptation model of the mismatch negativity (MMN), the sensitivity of this event‐related response to both acoustic and categorical information in speech sounds can be accounted for by assuming that (a) the degree of overlapping between neural representations of two sounds depends on both the acoustic difference between them and whether or not they belong to distinct phonetic categories, and (b) a release from stimulus‐specific adaptation causes an enhanced N1 obligatory response to infrequent deviant stimuli. On the basis of this view, we tested in Experiment 1 whether the N1 response to the second sound of a pair (S₂) would be more attenuated in pairs of identical vowels compared with pairs of different vowels, and in pairs of exemplars of the same vowel category compared with pairs of exemplars of different categories. The psychoacoustic distance between S₁ and S₂ was the same for all within‐category and across‐category pairs. While N1 amplitudes decreased markedly from S₁ to S₂, responses to S₂ were quite similar across pair types, indicating that the attenuation effect in such conditions is not stimulus specific. In Experiment 2, a pronounced MMN was elicited by a deviant vowel sound in an across‐category oddball sequence, but not when the exact same deviant vowel was presented in a within‐category oddball sequence. This adds evidence that MMN reflects categorical phonetic processing. Taken together, the results suggest that different neural processes underlie the attenuation of the N1 response to S₂ and the MMN to vowels.     

A cross-linguistic examination of cortical auditory evoked potentials for a categorical voicing contrast

Behavioral perceptions and cortical auditory evoked potentials (CAEPs) from native English (N=10) and Spanish speakers (N=10) were recorded for speech stimuli that constitute phonetically relevant categories of voicing. The stimuli were synthesized bilabial stop consonant-vowel syllables in a continuum ranging from/ba/to/pa/that varied in voice onset time (VOT) from 0 to 60 ms. Different behavioral perceptions were evidenced by significantly different categorical phonetic boundaries between the two groups (p<.0001). In contrast, there were no significant differences in CAEP component P1, N1, and P2 mean latencies or P1-N1 and N1-P2 amplitudes between groups (p>.05). Peak P1, N1, and P2 response latencies and P1-N1 and N1-P2 amplitudes increased significantly with increasing VOTs (p<.0001 and p<.001, respectively). There were no systematic changes in CAEP morphology that corresponded to listeners' perceptual categorical boundaries. These findings are consistent with the notion that changes in morphology of the P1-N1-P2 response are related to acoustical changes in speech sounds and are independent of phonetic categorization of voicing cues across language groups.     

Carbohydrate alters the trypanocidal activity of normal human serum with Trypanosoma brucei

Three categories of carbohydrates are distinguished based on their effects on the trypanocidal activity of normal human serum on Trypanosoma brucei. The first category includes carbohydrates such as glucose, mannose and fructose which are utilized by parasites as an energy source. These carbohydrates inhibit the trypanocidal activity in a concentration-dependent manner. The third category, represented by xylose and mannitol, are not energy sources to the parasites but inhibit the trypanocidal activity in a manner similar to the first category carbohydrate. However, at very high concentrations (≈ 140–150 mM), the inhibition is reversed. Glycerol is the only known carbohydrate belonging to the second category. Glycerol enhances the trypanocidal activity of normal human serum and of those sera which normally display no cytotoxic activity, although glycetol serves as an excellent energy source. On the basis of these results, the mechanisms by which these three categories of carbohydrate could alter the trypanocidal activity are discussed in terms of the interaction between a trypanocidal factor and the surface receptor.     

Do clinicians convey what they intend? Lay interpretation of verbal risk labels used in decision encounters

ObjectiveTo assess the numerical probabilities that individuals associate with frequently-used verbal labels relating to treatment outcomes and their association with medical context, age, gender, educational level, health literacy, and numeracy.MethodsVerbal labels (N = 11) were extracted from N = 90 audiotaped decision encounters in oncology. Three hundred Dutch adults, as proxies for newly-diagnosed cancer patients, assigned numerical probabilities to the labels in the context of cancer recurrence or nausea, and completed questions on their socio-demographic characteristics, health literacy and numeracy.ResultsWe found considerable variation in how individuals interpreted the verbal labels. Participants’ probability estimates of verbal labels was lower in the context of (the more serious) cancer recurrence compared to (less serious) nausea. Lower numerate participants differentiated less between labels. There was no association between participants’ estimates and age, gender, educational level or health literacy.ConclusionThere is considerable variation in how individuals interpret verbal labels frequently-used in decision encounters. Individuals seem to take base rates and severity of outcomes into account. Verbal labels may be less helpful to lower numerate individuals.Practice implicationsTo minimize misinterpretation and to improve patient-clinician decision making about health and care, we recommend to avoid the use of verbal labels only.     

The organization of the conceptual system: the case of the "object versus action" dimension

There are very numerous reports in the neuropsychological literature of patients showing, in naming and/or comprehension tasks, a disproportionate deficit for nouns in comparison with verbs or a disproportionate deficit for verbs in comparison with nouns. A number of authors advanced that, in at least some or even in every of these reported cases, the noun/verb dissociation in fact reflected an underlying conceptual deficit disproportionately affecting either object or action concepts. These patterns thus would put an additional constraint on theories of conceptual knowledge organization, which should be able to explain how brain damage could selectively disrupt the concepts of objects or the concepts of actions. We have reviewed 69 papers (published from 1984 to 2009) that reported a pattern of a noun or a verb disproportionate deficit in a single-case, multiple-case, or group study of brain-damaged patients with various aetiologies. From this review, we concluded that none of these studies provided compelling evidence in favour of the interpretation that the observed noun or verb disproportionate deficit arose at the conceptual processing level and, accordingly, that this level may be organized according to the "object/action" dimension. Furthermore, we argue that investigating conceptual impairments in brain-damaged patients according to the "object/action" dichotomy is not empirically fruitful if the purpose is to inform theories of conceptual knowledge organization. In order to provide evidence relevant to these theories, one needs to consider finer grained distinctions within both the object and the action category when investigating the scope of the patients' conceptual impairment.