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PubMed1995

Computerized measurement of the content analysis of natural language for use in biomedical and neuropsychiatric research.

Over several decades, the senior author, with various colleagues, has developed an objective method of measuring the magnitude of commonly useful and pertinent neuropsychiatric and neuropsychological dimensions from the content and form analysis of verbal behavior and natural language. Extensive reliability and validation studies using this method have been published involving English, German, Spanish and many other languages, and which confirm that these Content Analysis Scales can be reliably scored cross-culturally and have construct validity. The validated measures include the Anxiety Scale (and six subscales), the Hostility Outward Scale (and two subscales), the Hostility In Scale, the Ambivalent Hostility Scale, the Social Alienation-Personal Disorganization Scale, the Cognitive Impairment Scale, the Depression Scale (and seven subscales), and the Hope Scale. Here, the authors report the development of artificial intelligence (LISP based) software that can reliably score these Content Analysis Scales, whose achievement facilitates the application of these measures to biomedical and neuropsychiatric research.

Diagnosis, Computer-Assisted↗
PubMed2004

Hemodynamic differences in the activation of the prefrontal cortex: attention vs. higher cognitive processing.

Both simple attention tasks (e.g. letter cancellation) and most tasks of higher cognitive processing (e.g. word generation) are known to activate the dorsolateral prefrontal cortex (PFC). While attention and higher cognitive processing differ phenomenologically, with attention tasks requiring great subjective effort despite their simplicity, possible physiological differences in the activation of the PFC between the two types of cognitive processing have remained uninvestigated. Hemodynamic changes in the PFC during activation due to tasks of attention and those of higher cognitive processing were examined using near-infrared spectroscopy in 10 Japanese and 10 American healthy adults. In tasks of higher cognitive processing, which included both verbal and non-verbal tasks, the concentration of oxygenated hemoglobin ([HbO2]) increased, and that of deoxygenated hemoglobin ([HbR]) decreased, with an increase in the tissue hemoglobin saturation (THS). In tasks of attention, which consisted of the letter cancellation and continuous performance test, both [HbO2] and [HbR] increased, with no significant changes in the THS observed. The distinctive patterns of hemodynamic changes were not affected by the factors of task difficulty or language. The change in [HbR] may be a physiological marker of the prefrontal lobe activation that discriminates between attention and higher cognitive processing. The increase in [HbR] suggests increased oxygen consumption of the PFC during tasks of attention, which might be related to the disproportionately great subjective effort associated with sustained attention. The physiological alteration in hemodynamic patterns according to changes in cognition needs to be examined in subjects with prefrontal lobe dysfunction, such as schizophrenia and mood disorder.

Adolescent↗
PubMed1990

Automatic memory processes in patients with dementia-Alzheimer's type (DAT).

We examined patients with Dementia-Alzheimer's Type, depression, and matched controls on tasks designed to compare automatic (monitoring frequency and modality) and effortful (free recall) processing of words and pictures. The results demonstrated that depressed patients performed poorly only when conditions required effortful processing, but DAT patients performed poorly under all conditions. There was almost no overlap in scores between DAT and elderly depressed patients on one of the measures of automatic processing suggesting that this measure may be clinically useful. The results suggest that automatic memory processes can be partially dissociated from effortful memory processes, but that both types of operations are impaired in DAT patients.

Aged↗
PubMed2005

Patients with hemianopic alexia adopt an inefficient eye movement strategy when reading text.

Patients with an acquired homonymous hemianopia often adapt over a period of a few months to compensate for some of the impairments caused by their visual field defect. Changes in their eye movement patterns have been demonstrated as performance on visual tasks improves with time; however, these patients often complain of persistent text reading problems. Using a video-based eye-movement tracking system, we investigated the text reading behaviour of patients with established hemianopic alexia (>6 months post deficit), a condition affecting left-to-right readers, with a homonymous field defect that encroaches into their right foveal/parafoveal visual field. Word-based analyses of text reading are standard in experiments involving normal readers, but this is the first time these methods have been extended to patients with hemianopic alexia. Using this method, we compared the patients' reading scanpaths to those generated by normal controls reading the same passages, and a random model generated by matching the patients' eye movement data to random permutations of the text they read. We demonstrate that patients adopt an inefficient reading strategy, fixating to the left of the preferred viewing location of words of four letters and longer. Fixating to the left of the normal preferred viewing location not only results in less of the fixated word being processed by the language system; ensuing fixations are also more likely to land within the same word (a refixation). It is this refixation rate that is the main factor in slowing reading times in these patients. Our data suggests that patients are able to extract some useful visual information from text to aid the planning of reading scanpaths as their behaviour differs critically from the random model. Potential reasons for this patient group failing to produce an effective reading strategy are discussed.

Adult↗
PubMed2004

BCI Competition 2003--Data set IIb: support vector machines for the P300 speller paradigm.

We propose an approach to analyze data from the P300 speller paradigm using the machine-learning technique support vector machines. In a conservative classification scheme, we found the correct solution after five repetitions. While the classification within the competition is designed for offline analysis, our approach is also well-suited for a real-world online solution: It is fast, requires only 10 electrode positions and demands only a small amount of preprocessing.

Algorithms↗
PubMed2004

BCI Competition 2003--Data set IIb: enhancing P300 wave detection using ICA-based subspace projections for BCI applications.

An algorithm based on independent component analysis (ICA) is introduced for P300 detection. After ICA decomposition, P300-related independent components are selected according to the a priori knowledge of P300 spatio-temporal pattern, and clear P300 peak is reconstructed by back projection of ICA. Applied to the dataset IIb of BCI Competition 2003, the algorithm achieved an accuracy of 100% in P300 detection within five repetitions.

Algorithms↗
PubMed2004

Digit and command interpretation for electronic book using neural network and genetic algorithm.

This paper presents the interpretation of digits and commands using a modified neural network and the genetic algorithm. The modified neural network exhibits a node-to-node relationship which enhances its learning and generalization abilities. A digit-and-command interpreter constructed by the modified neural networks is proposed to recognize handwritten digits and commands. A genetic algorithm is employed to train the parameters of the modified neural networks of the digit-and-command interpreter. The proposed digit-and-command interpreter is successfully realized in an electronic book. Simulation and experimental results will be presented to show the applicability and merits of the proposed approach.

Algorithms↗
PubMed2004

All talk and no action: a transcranial magnetic stimulation study of motor cortex activation during action word production.

A number of researchers have proposed that the premotor and motor areas are critical for the representation of words that refer to actions, but not objects. Recent evidence against this hypothesis indicates that the left premotor cortex is more sensitive to grammatical differences than to conceptual differences between words. However, it may still be the case that other anterior motor regions are engaged in processing a word's sensorimotor features. In the present study, we used single- and paired-pulse transcranial magnetic stimulation to test the hypothesis that left primary motor cortex is activated during the retrieval of words (nouns and verbs) associated with specific actions. We found that activation in the motor cortex increased for action words compared with non-action words, but was not sensitive to the grammatical category of the word being produced. These results complement previous findings and support the notion that producing a word activates some brain regions relevant to the sensorimotor properties associated with that word regardless of its grammatical category.

Acoustic Stimulation↗
PubMed2004

Counter-propagation network with variable degree variable step size LMS for single switch typing recognition.

Morse code is now being harnessed for use in rehabilitation applications of augmentative-alternative communication and assistive technology, including mobility, environmental control and adapted worksite access. In this paper, Morse code is selected as a communication adaptive device for disabled persons who suffer from muscle atrophy, cerebral palsy or other severe handicaps. A stable typing rate is strictly required for Morse code to be effective as a communication tool. This restriction is a major hindrance. Therefore, a switch adaptive automatic recognition method with a high recognition rate is needed. The proposed system combines counter-propagation networks with a variable degree variable step size LMS algorithm. It is divided into five stages: space recognition, tone recognition, learning process, adaptive processing, and character recognition. Statistical analyses demonstrated that the proposed method elicited a better recognition rate in comparison to alternative methods in the literature.

Adult↗
PubMed1989

Reading strategies of fast and slow readers.

In three subject-paced experiments we evaluated reading patterns at the word, line, and sentence level for fast and slow readers. A moving-window method was used to collect word reading times for natural texts. At the word level, reading times of word N were influenced by features of word N-1 for fast readers but not for slow readers. The lag effect exhibited by fast readers indicates that they continue to process a word when it is no longer in view, thus limiting the notion of immediate processing. Contrary to our initial expectation that fast readers would process only a single new argument from a sentence, whereas slow readers would process several new arguments, we found that both reader groups adopted a many-argument strategy. However, fast and slow readers differed in terms of the text units (lines vs. sentences) defining the new-argument effects: Fast readers exhibited greater new-argument effects relative to lines, whereas slow readers exhibited greater new-argument effects relative to sentences. Specifically, slow readers integrated the new arguments primarily at the end of the sentence, whereas fast readers did so at line boundaries. These results are discussed in terms of a buffer-and-integrate model of reading comprehension.

Adult↗
PubMed1998

Event-related potentials to stimuli with emotional impact in posttraumatic stress patients.

BACKGROUND: Psychophysiological research has given conflicting results with respect to whether the abnormal physiologic responses observed in posttraumatic stress disorder (PTSD) reflect a general abnormality or are linked to trauma-related stimuli. We studied differences in the central nervous processing of words with emotional impact in survivors after a ship fire disaster. METHODS: Event-related potentials were studied in 11 survivors with posttraumatic stress pathology, and compared with 9 survivors without such pathology. Nonwords and words with negative or positive emotional valence were used as distractors in a P3 oddball paradigm. RESULTS: PTSD subjects had increased N1 latency to standard tones and increased positive amplitude to both words and nonwords compared with controls, occurring between 200 and 350 msec after stimulus onset. The amplitudes to emotionally meaningful words were significantly related to Clinician-Administered PTSD Scale-assessed PTSD dimensions, in particular avoidance and arousal. CONCLUSIONS: The abnormality in information processing observed in PTSD patients seems in part to be linked with increased attention, in part with emotional responses to the trauma. Intrusion was mainly related to the processing of nonwords, while arousal and avoidance were related to event-related potential amplitudes to emotionally meaningful words, suggesting that intrusion has a different neurobiological basis than arousal and avoidance.

Acoustic Stimulation↗
PubMed1983

[Pre-verbality in focusing and the need for self check. An attempt at "focusing check"].

Though the Focusing process is not entirely non-verbal, in Focusing, careful attention is paid by the Focuser and the Listener to the pre-verbal experiential process. In other words, Focusing involves attending to the felt sense that is not easily expressed in words immediately. Hence, during the process of learning to Focus, the Focusing teacher attempts to communicate the experiences of Focusing to the student which are not easily done by words. Due to such difficulties, the Focusing student may (and quite frequently does) mistake the experiential process in Focusing with other processes. Often, the felt sense can be confused with other phenomena such as "autogenic discharge". Also the Focuser may not stay with the felt sense and drift into "free association" or frequently, certain processes in "meditation" can be confused with Focusing. Therefore, there is a need for a "check" by which the Focusing student can confirm the Focusing experience for himself. For the Focusing student, such a "check" serves not only to confirm the Focusing process, but also an aid to learning Focusing. We will report here a "Focusing Check" which we developed by translating Eugene Gendlin's "Focusing Check" and making several modifications in it so that it will be more understandable to the Japanese. Along with the "Focusing Check" we developed, the authors discuss the need for such a check.

Attention↗
PubMed2006

Blood glucose changes and memory: effects of manipulating emotionality and mental effort.

Increasing the emotionality of target material often facilitates memory performance which may be linked to the liberation of glucose. Conversely, increasing mental effort leads to reduced performance and measurable falls in blood glucose. A 2 x 2, parallel groups experiment examined these two phenomena directly by assessing blood glucose levels and memory for neutral and emotional word lists, both with and without a secondary task. Co-performing the secondary task significantly reduced blood glucose in the neutral word condition only and resulted in a global reduction of memory performance in both neutral and emotional word conditions. Processing emotional material resulted in significantly raised blood glucose levels, however, there was no advantage for memory of emotional words. A follow-up study confirmed that the emotionality manipulation was effective. We conclude that there exists a clear relationship between reduced blood glucose and impaired memory performance during periods of mental effort. However, the relationship between physiological and cognitive processes associated with processing emotional material are more complex.

Adult↗
PubMed2001

Functional differences in the semantic processing of concrete and abstract words.

There is considerable debate as to whether the semantic system is a unitary one in which meanings are available in a peculiar, perceptual-free format, or whether it is functionally segregated into anatomically discrete, modality-specific but semantic regions. In the former case, concrete and abstract words should not differ in the amount of activation of semantic areas. Neuroimaging studies in this field are, however, far from conclusive, and one reason for this may be that the degree of imageability of the stimuli - probably a crucial variable - has not been considered. Recognition Potential (RP) reflects semantic processing and appears to originate in basal extrastriate regions involved in semantic processing. In this study, we compared the RP of concrete and abstract words that actually differ in their degree of imageability. Results indicate that the semantic processing areas in which the RP originates display a higher activation for concrete (more imageable) material, but that abstract material also evokes a notably larger RP component compared with pseudowords or unpronounceable letter strings. Accordingly, the study appears to suggest that there is no full functional segregation of the semantic systems. Rather, our data support the existence of a semantic system that is specialised in concrete, imageable material, and that is also activated, though to a lower extent, by abstract material.

Adolescent↗
PubMed1991

Generating makes words memorable, but so does effective reading.

In many experiments, memorial benefits have been found when subjects generate items from fragments rather than read items in their complete forms. Does generation cause this difference, or are subjects disposed to adopt different strategies when generating as opposed to reading? If generating causes the difference, items processed in the same way apart from a generative stage should therefore benefit from that generative stage. Our experiments did result in benefits for generating as opposed to reading, but only when the readers processed the words poorly--by pronouncing them. When the readers processed the items well, by imagining them, generating was no better than reading. A new generation effect was found in metamemory. Subjects thought they would remember more generated items than read items; however, the act of making the prediction entailed meaningful processing, and the generated items were not actually remembered better than the read ones.

Adult↗
PubMed1987

Lexical acquisition in alcoholic Korsakoff psychosis.

Recent studies have underlined the importance of the distinction between "declarative" and "procedural" aspects of memory functioning. The purpose of the present study is to evaluate the relative deficits in these two aspects of anterograde memory in an amnesic population with midline diencephalic lesions, and to determine whether this apparently fundamental distinction in memory types is honored even under real-world conditions. Eight alcoholic Korsakoff patients were examined for their lexical acquisition capacity, including both their application of word-learning procedures to a new lexical domain and their eventual recall of the facts represented by the new word. The findings revealed that each Korsakoff patient successfully applies at least some of the procedures subserving the word-learning process to the new lexical domain. By comparison, the Korsakoff patients subsequently acquire little of the factual knowledge represented by the new word. Specifically, almost all of the patients recognize only the object used during the exposure period to demonstrate the new word. Quantitative and qualitative features of the patients' declarative and procedural memory deficits are discusses in the context of real-world processing advantages and limitations.

Adult↗
PubMed2003

Recognition by top-down and bottom-up processing in cortex: the control of selective attention.

Visual recognition is achieved by a hierarchy of bidirectionally connected cortical areas. The entry of signals into higher areas involves the serial sampling of information within a movable window of attention. Here we explore how the cortex can move this window and integrate the sampled information. To make this concrete, we modeled the process of visual word recognition by hierarchical cortical areas representing features, letters, and words. At the start of the recognition process, nodes representing all contextually possible words are active. Simple connectivity rules allow a parallel top-down (T-D) computation of the relative probability of each feature at each location given the set of active words. This information is then used to guide the window of attention to information-rich features (e.g., a feature that is present in the visual image but has lowest probability). Bottom-up processing of this feature excludes words that do not contain it and leads to T-D recomputation of feature probabilities. Recognition occurs after several such cycles when all but one word has been excluded. We show that when 950 words are stored in long-term memory, recognition occurs after an average of 4.9 cycles. Because covert attention can be moved every 20-30 ms, word recognition could be as fast as determined experimentally (<200 ms of cortical processing). This model accounts for the findings that recognition time depends logarithmically on set size, recognition time is reduced when context reduces the number of possible targets, the time to classify a nonword decreases when its approximation to English decreases, and in high level cortex, the firing of neurons tuned to an object increases progressively as its recognition occurs. More generally the model provides a physiologically plausible view of how bi-directional signal flow in cortex guides attention to produce efficient recognition.

Animals↗