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Biomedical subjects

K Hugdahl

Publications and source records attributed to K Hugdahl.

At least 19 recordsLinked to original sources
PubMed2006

Neuropsychological test profiles in schizophrenia and non-psychotic depression.

OBJECTIVE: The study examined to what degree schizophrenia is characterized by a neuropsychological (NP) test profile specific in shape and level compared with depression and normal functioning. METHOD: Fifty-three patients with schizophrenia, 45 with non-psychotic depression, and 50 normals were assessed with a comprehensive NP test battery and clinical instruments. NP test scores were factor analyzed into seven composite scores. RESULTS: Schizophrenia patients performed significantly below normals across all seven composite scores, whereas depression patients were impaired in two. Verbal memory was most impaired. Sixty-two percent of schizophrenia patients were moderately or severely impaired, the corresponding figure for depression was 28%. Impairment was moderately associated with IQ level and clinical symptom load in schizophrenia, but not in depression. CONCLUSION: Schizophrenia is characterized by deficits across a wide range of NP functions. Thirty-eight percent of the patients are within normal limits. A mild and limited NP disturbance is apparent in depression.

Adult↗
PubMed2006

Positive symptoms and duration of illness predict functional laterality and attention modulation in schizophrenia.

OBJECTIVE: Dichotic listening (DL) performance in schizophrenia, reflecting hemispheric asymmetry and the functional integrity of the left temporal lobe, can vary with clinical characteristics. Previous studies have not taken the co-linearity of clinical variables into account. The aim of the present study was to evaluate the roles of positive symptoms and duration of illness in DL through Structural Equation Modeling (SEM), thus allowing for complex relationships between the variables. METHOD: We pooled patients from four previous DL studies to create a heterogeneous group of 129 schizophrenic patients, all tested with a consonant-vowel syllables DL procedure that included attentional instructions. RESULTS: A model where positive symptoms predicted a laterality component and duration of illness predicted an attention component in DL was confirmed. CONCLUSION: Positive symptoms predicted reduced functional laterality, suggesting involvement of left temporal lobe language processing. Duration of illness predicted impaired attention modulation, possibly reflecting the involvement of frontotemporal networks.

Adolescent↗
PubMed2003

Attention profile in schizophrenia compared with depression: differential effects of processing speed, selective attention and vigilance.

OBJECTIVE: The aim of the study is to investigate whether subjects with schizophrenia and major depression display attention deficits for different reasons. METHOD: Subjects with schizophrenia (n = 53), recurrent major depression (n = 50) and normal controls (n = 50) were administered with 11 measures of processing speed, selective attention and vigilance. Indices of basal speed, speeded attention, non-speeded attention and vigilance were computed. RESULTS: Both clinical groups were impaired on all chronometric tests. The schizophrenic subjects were also more impaired on speeded attention compared with basal processing speed. Only the schizophrenics were impaired on the non-speeded measures of selective attention. Compared with the schizophrenics, the depressives showed a decrement in vigilance. CONCLUSION: Reduced performance on attention tests in major depression is because of a non-specific speed reduction and loss of vigilance consistent with lack of effort. In addition to generally impaired processing speed, the schizophrenic subjects exposed a deficit in selective attention, indicating executive dysfunction.

Adult↗
PubMed2001

Honig's model of working memory and brain activation: an fMRI study.

The present study investigated changes in neuronal activation with fMRI related to Honig's model of working memory, which is much less studied compared with other working memory models. In contrast to other studies which have applied recognition procedures, the primary aim with the present study was to examine brain activation when subjects had to continuously recall and forget items held in working memory. The results showed that the mid-ventrolateral frontal cortex was particularly activated in the left hemisphere, whereas the mid-dorsolateral frontal cortex was particularly activated in the right hemisphere during execution of the working memory task. The findings are discussed in relation to process- and domain-specific accounts of working memory.

Adult↗
PubMed2001

[Surgical treatment of normal pressure hydrocephalus].

Normal pressure hydrocephalus (NPH) is an important diagnosis to keep in mind, i.e. the possibility that NPH and not a neurodegenerative disease causes the patient's symptoms with ataxia, urinary incontinence and dementia. Clinical improvement, sometimes a complete reversal of the symptoms, may be seen after a simple surgical procedure. This prospective study was performed by testing eight consecutively shunted patients with a walking test and a cognitive test battery pre- and postoperatively. Improvement 3-4 months after the shunting procedure suggests that NPH was present in six of eight patients. Walking ability was improved after surgery, also in patients with severe dementia. Severe dementia caused by NPH is hardly reversible, though cognitive tests may indicate some improvement. However, early surgical treatment of NPH in patients not suffering from a dementia according to the Mini Mental Status Test may bring improvement in some cognitive functions. Patients with both clinical and radiological signs of normal pressure hydrocephalus should be offered a shunting procedure.

Aged↗
PubMed2001

Auditory laterality and attentional deficits after thalamic haemorrhage.

Thalamic lesions have been shown to produce severe cognitive deficits involving language and memory. A majority of the studies have reported cognitive deficits after lesions in the anterior and dorsomedial thalamic nuclei. We report five case studies of effects on language processing after postero-dorsal thalamic haemorrhages. Four of the patients had lesions on the right side, and one patient had a lesion on the left side. Effects on language processing were investigated with the dichotic listening test with consonant-vowel syllables. This test, in which conflicting auditory stimuli are presented simultaneously to the two ears, has been used to probe differences in language processing in the left and right hemispheres. The four patients with right-sided lesions reported almost none of the syllables presented to the left ear, and were unable to modify this massive right ear advantage by directing attention to the left or right ear. The patient with a left-sided lesion showed a weaker left ear advantage, and was able to modify his responses by shifting attention, to an extent similar to that of healthy reference individuals. When tested with monaural stimulus presentation, the scores of all patients rose to almost 100% correct for each ear. The pattern of effects with dichotic stimuli under different instructional conditions cannot be accounted for in purely structural terms, and indicates that lesions in the posterior part of the thalamus, including the pulvinar nucleus and medial geniculate body, produce deficits not only in processing of complex auditory stimuli but also in the allocation of attention to input from one ear or the other.

Adolescent↗
PubMed2001

Behaviour problems in children with dyslexia.

The association between behaviour problems and dyslexia was assessed in a population sample of 10- to 12-year-old children. Twenty-five dyslexic children and a matched control group were recruited through a screening in primary schools in the city of Bergen, Norway. For the assessment of behaviour problems the Child Behavior Checklist (CBCL), Teacher Self Report (TRF), and Youth Self Report (YSR) were filled out by parents, teachers, and children, respectively. Information on health and developmental factors were obtained from parents on a separate questionnaire designed for the study. The dyslexic group had significantly more behaviour problems than the control group according to both the CBCL and the TRF. On the YSR there was no significant difference between the groups. Dyslexic children had higher CBCL and TRF scores on the Total Behaviour Problem scale, the Internalizing and Externalizing subdomains, and the Attention problem subscale. The groups differed in social background, prenatal risk factors, birth weight, preschool language problems, and IQ, but these variables showed no relationship to the level of behaviour problems in the present sample. We conclude that pre-adolescent dyslexic children show a wide range of behaviour problems that cannot be attributed to social or developmental background variables.

Case-Control Studies↗
PubMed2001

Different brain areas activated during imagery of painful and non-painful 'finger movements' in a subject with an amputated arm.

The purpose of the present study was to investigate differences in brain activation with functional magnetic resonance imaging (fMRI) during imagery of painful and non-painful 'finger movements' and 'hand positioning' in a subject with an amputated arm. The subject was a right-handed man in his mid-thirties who lost his right arm just above the elbow in a car-train accident. MRI was performed with a 1.5 T Siemens Vision Plus scanner. The basic design involved four conditions: imagining 'painful finger movements', 'non-painful finger movements', 'painful hand positioning', 'non-painful hand positioning'. Imagery of finger movements uniquely activated the contralateral primary motor cortex which contains the classic 'hand area'. The lateral part of the anterior cerebellar lobe was also activated during imagery of finger movements. Imagery of pain uniquely activated the somatosensory area, and areas in the left insula and bilaterally in the ventral posterior lateral nucleus of the thalamus. It is suggested that the insula and thalamus may involve neuronal pathways that are critical for mental processing of pain-related experiences, which may relate to a better understanding of the neurobiology of phantom limb pain.

Adult↗
PubMed2001

Common pathways in mental imagery and pain perception: an fMRI study of a subject with an amputated arm.

The present paper reviews data from two previous studies in our laboratory, as well as some additional new data, on the neuronal representation of movement and pain imagery in a subject with an amputated right arm. The subject imagined painful and non-painful finger movements in the amputated stump while being in a MRI scanner, acquiring EPI-images for fMRI analysis. In Study I (Ersland et al., 1996) the Subject alternated tapping with his intact left hand fingers and imagining "tapping" with the fingers of his amputated right arm. The results showed increased neuronal activation in the right motor cortex (precentral gyrus) when tapping with the fingers of the left hand, and a corresponding activation in the left motor cortex when imagining tapping with the fingers of the amputated right arm. Finger tappings of the intact left hand fingers also resulted in a larger activated precentral area than imagery "finger tapping" of the amputated right arm fingers. In Study II (Rosen et al., 2001 in press) the same subject imagining painful and pleasurable finger movements, and still positions of the fingers of the amputated arm. The results showed larger activations over the motor cortex for movement imagining versus imagining the hand being in a still position, and larger activations over the sensory cortex when imagining painful experiences. It can therefore be concluded that not only does imagery activate the same motor areas as real finger movements, but also that adding instructions of pain together with imaging moving the fingers intensified the activation compared with adding instructions about non-painful experiences. From these studies, it is clear that areas activated during actual motor execution to a large extent also are activated during mental imagery of the same motor commands. In this respect the present studies add to studies of visual imagery that have shown a similar correspondence in activation between actual object perception and imagery of the same object.

Adult↗
PubMed2001

Age effects in dichotic listening to consonant-vowel syllables: interactions with attention.

A relatively large sample of individuals (N = 240) ranging from 7 to 70 years were studied with the dichotic listening (DL) technique as a measure of language lateralization. Two questions were asked: (a) Is there a developmental effect for the right-ear advantage (REA) with age? (b) Is there a developmental effect for attentional modulation of the REA? The participants were all right-handed, healthy individuals tested in Sweden and Norway. The stimuli were dichotic presentations of consonant-vowel (CV) syllable pairs. There were 3 different attentional conditions: nonforced (NF) attention, with no specific instructions about focusing of attention; forced-right (FR) attention, with instructions to focus attention on the right-ear stimulus; and forced-left (FL) attention, with instructions to focus attention on the left-ear stimulus. The results showed a REA in all age groups, except for the 9-year-olds, in the NF condition. In the FR condition, all age groups showed a REA. The youngest age groups did not, however, increase the REA to the same degree as the older age groups, as indicated by the significant age x ear interaction. In the FL condition, all age groups, with the exception of the youngest groups, showed a left-ear advantage (LEA). It is concluded that the REA effect in DL is subject to developmental effects and that attentional effects on laterality also develop with increasing age.

Adolescent↗
PubMed2000

Effects of attention on dichotic listening: an 15O-PET study.

The present study investigated the effect of attention on brain activation in a dichotic listening situation. Dichotic listening is a technique to study laterality effects in the auditory sensory modality. Two different stimuli were presented simultaneously, one in each ear. Twelve subjects listened to lists of consonant-vowel syllables, or short musical instrument passages, with the task of detecting a "target" syllable or musical instrument by pressing a button. The target stimulus appeared an equal number of times in the left and right ear. The subjects were instructed to either concentrate on the stimuli presented in both ears, or only on the left or right ear stimulus. Brain activation was measured with 15O-PET, and significant changes in regional normalized counts (rNC) were evaluated using statistical parametric mapping (SPM96) software. Concentrating on either the right or left ear stimulus significantly decreased activity bilaterally in the temporal lobes compared to concentrating on both ear stimuli, at the expense of an increased activation in the right posterior and inferior superior parietal lobe. The CV-syllables activated areas corresponding to the classic language areas of Broca and Wernicke. The musical instrument stimuli mainly activated areas in visual association cortex, cerebellum, and the hippocampus. An interpretation of the findings is that attention has a facilitating effect for auditory processing, causing reduced activation in the primary auditory cortex when attention is explicitly recruited. The observed activations in the parietal lobe during the focused attention conditions could be part of a modality non-specific "attentional network".

Adult↗
PubMed2000

Neurocognitive correlates of stereotactic thalamotomy and thalamic stimulation in Parkinsonian patients.

In the present paper we have reviewed five different studies that relate to neuropsychological consequences of stereotactic thalamotomy and thalamic stimulation in patients with Parkinson's disease. The neuropsychological results are in a strict sense confined to thalamotomy and thalamic stimulation, although the more general message of the importance of investigating cognitive functions before and after surgery applies to other stereotactic techniques for surgical treatment of movement disorders as well. It is argued in the paper that stereotactic thalamotomy provides a unique model for basic research on the neuropsychology of the thalamus, while in return, neuropsychological tests for cognitive dysfunction after surgery may be the most important clinical follow-up. Three general conclusions seem warranted from the data. (1) Parkinsonian patients are impaired on a range of cognitive functions, including language processing, memory, and executive functions. (2) Stereotactic thalamotomy does not further impair the patient; instead, we observed improvement on some tests, particularly verbal memory. (3) In general, there does not seem to be a laterality effect, depending on which side the thalamotomy lesion is applied. An exception to this are dichotically presented simple speech sounds and autonomic responses. In both instances, left-sided brain stimulation produced enhanced performance, while lesioning the left thalamus impaired dichotic listening performance. Finally, we present a new hypothesis for a mechanism behind the thalamotomy effect, based in part on changes in arousal thresholds.

Aged↗
PubMed2000

Lateralization of cognitive processes in the brain.

The lateralization of cognitive processes in the brain is discussed. The traditional view of a language-visuo/spatial dichotomy of function between the hemispheres has been replaced by more subtle distinctions. The use of magnetic resonance imaging (MRI) to study brain morphology has resulted in a renewed focus on the relationship between structural and functional asymmetry. Focus has been on the role played by the planum temporale area in the posterior part of the superior temporal gyrus for language asymmetry, and the possible significance of the larger left planum. The dichotic listening technique is used to illustrate the difference between bottom-up, or stimulus-driven laterality versus top-down, or instruction-driven laterality. It is suggested that the hemispheric dominance observed at any time is the sum result of the dynamic interaction between bottom-up and top-down processing tendencies. Stimulus-driven laterality dominance is always monitored and modulated through top-down cognitive processes, like shifting of attention and changes in arousal. A model of top-down modulation of bottom-up laterality is presented with special reference to the understanding of psychiatric disorders.

Adult↗
PubMed2000

Planum temporale, planum parietale and dichotic listening in dyslexia.

A reduction or reversal of the normal leftward asymmetry of the planum temporale (PT) has been claimed to be typical of dyslexia, although some recent studies have challenged this view. In a population-based study of 20 right-handed dyslexic boys and 20 matched controls, we have measured the PT and the adjacent planum parietale (PP) region in sagittal magnetic resonance images. For the PT, mean left and right areas and asymmetry coefficients were compared. Since a PP area often could not be identified in one or both hemispheres, a qualitative comparison was used for this region. The total planar area (sum of PT and PP) was also compared between the two groups. A dichotic listening (DL) test with consonant-vowel syllables was administered to assess functional asymmetry of language. The results showed a mean leftward PT asymmetry in both the dyslexic and the control group, with no significant difference for the degree of PT asymmetry. Planned comparisons revealed however, a trend towards smaller left PT in the dyslexic group. In control children, but not in the dyslexic children, a significant correlation between PT asymmetry and reading was observed. A mean leftward asymmetry was also found for the total planar area, with no difference between the groups for the degree of asymmetry. Significantly fewer dyslexic children than control children showed a rightward asymmetry for the PP region. Both groups showed a normal right ear advantage on the DL task, with no significant difference for DL asymmetry. No significant correlation was observed between PT asymmetry and DL asymmetry. The present population-based study adds to recent reports of normal PT asymmetry in dyslexia, but indicates that subtle morphological abnormalities in the left planar area may be present in this condition.

Child↗
PubMed2000

Lonely traits and concomitant physiological processes: the MacArthur social neuroscience studies.

Loneliness is a complex set of feelings encompassing reactions to unfulfilled intimate and social needs. Although transient for some individuals, loneliness can be a chronic state for others. Prior research has shown that loneliness is a major risk factor for psychological disturbances and for broad-based morbidity and mortality. We examined differences between lonely and socially embedded individuals that might explain differences in health outcomes. Satisfying social relationships were associated with more positive outlooks on life, more secure attachments and interactions with others, more autonomic activation when confronting acute psychological challenges, and more efficient restorative behaviors. Individuals who were chronically lonely were characterized by elevated mean salivary cortisol levels across the course of a day, suggesting more discharges of corticotropin-releasing hormone and elevated activation of the hypothalamic-pituitary-adrenocorticol axis. An experimental manipulation of loneliness further suggested that the way in which people construe their self in relation to others around them has powerful effects on their self concept and, possibly, on their physiology.

Humans↗
PubMed2000

Individual differences in neurobehavioral measures of laterality and interhemispheric function as measured by dichotic listening.

This article presents analysis of dichotic listening performance in 57 healthy men and women aged 20 to 72 years. The data are presented as a means to cover 2 theoretical issues relevant to the biobehavioral study of laterality and interhemispheric relations. First, the sensitivity of dichotic listening performance to factors such as sex, age, and their interactions was examined. Dichotic listening asymmetry scores were found to vary as a function of sex, age, handedness, and family history of developmental language disorders. The effects of sex and age were then explored in relation to a comparison of nonforced and unilaterally focused test conditions. The results suggest that even within a healthy, normative sample of human participants, individuals vary not only in their underlying perceptual asymmetries for auditory input, but also in the manner in which such asymmetries interact with other higher order cognitive functions.

Adult↗
PubMed2000

Alcoholics' selective attention to alcohol stimuli: automated processing?

OBJECTIVE: This study investigated alcoholics' selective attention to alcohol words in a version of the Stroop color-naming task. METHOD: Alcoholic subjects (n = 23) and nonalcoholic control subjects (n = 23) identified the color of Stroop versions of alcohol, emotional, neutral and color words. Manual reaction times (RTs), skin conductance responses (SCRs) and heart rate (HR) were recorded. RESULTS: Alcoholics showed overall longer RTs than controls while both groups were slower in responding to the incongruent color words than to the other words. Alcoholics showed longer RTs to both alcohol (1522.7 milliseconds [ms]) and emotional words (1523.7 ms) than to neutral words (1450.8 ms) which suggests that the content of these words interfered with the ability to attend to the color of the words. There was also a negative correlation (r = -.41) between RT and response accuracy to alcohol words for the alcoholics, reflecting that the longer time the alcoholics used to respond to the color of the alcohol words, the more incorrect their responses were. The alcoholics also showed significantly greater SCRs to alcohol words (0.16 microSiemens) than to any of the other words (ranging from 0.04-0.08 microSiemens), probably reflecting the emotional significance of the alcohol words. Finally, the alcoholics evidenced smaller HR acceleration to alcohol (1.9 delta bpm) compared to neutral (2.8 delta bpm), which could be related to difficulties alcoholics experience in terminating their attention to the alcohol words. CONCLUSIONS: These findings indicate that it is difficult for alcoholics to regulate their attention to alcohol stimuli, suggesting that alcoholics' processing of alcohol information is automated.

Adult↗