Obstacle avoidance during human walking: transfer of motor skill from one leg to the other.

The aim of this study was to evaluate whether a newly acquired locomotor skill can be transferred to the mirror condition. Subjects were trained to step over an obstacle on a treadmill, the appearance of which was signalled by an acoustic stimulus, while visual information was prevented. Feedback information about foot clearance was provided by acoustic signals. During two successive runs (each consisting of 100 steps over the obstacle) the same leg was leading (i.e. the leg crossing the obstacle first). In the following third run, the leading and trailing legs were changed. During each of the three successive runs the adaptational changes were analysed by recording leg muscle electromyographic (EMG) activity, joint angle trajectories and foot clearance over the obstacle. The training effect gained between the first and second runs and the transfer to the mirror condition (third run) were evaluated. Adaptational changes of all measures, except ankle joint trajectory, could to a significant extent be transferred to the mirror condition. No side-specific differences in the amount of transfer were found, neither from the right to the left side, nor vice versa. These observations are at variance with adaptational changes observed during split-belt walking or one-legged hopping on a treadmill, where no transfer to the mirror condition occurred. It is assumed that this might be due to the specific requirements of the tasks and the leg muscles involved. While in the split-belt and hopping experiments leg extensor muscles are mainly involved, leg flexors predominate in the performance of the present task. It is hypothesised that the learning effects observed in the present experiments are mediated at a higher level (e.g. brainstem) of locomotor control.

Obstacle avoidance during human walking: learning rate and cross-modal transfer.

1. The aim of this study was to investigate the significance of specific afferent information during motor learning. Blindfolded subjects stepped over an obstacle on a treadmill while different stimuli (acoustic (ACU), somatosensory (SOM) and light flash (LED)) signalled the approaching obstacle. The effect of the above stimuli was then evaluated and compared to full vision (VIS) locomotion. In the non-visual conditions feedback information about the performance was provided by an acoustic signal. 2. Using each of the different stimuli for information the level of subject performance was assessed by noting foot clearance and analysing both leg muscle electromyographic activity and movement trajectories during three successive runs. Each of these runs consisted of 100 steps over the obstacle. 3. The best performance at the onset of the first run was achieved during the VIS condition. When the VIS condition (run 1 + 2) was followed by ACU or SOM information or when the ACU condition (run 1 + 2) was followed by LED, little cross-modal transfer (CMT) occurred, i.e. adaptation in run 3 started again at a low level of performance. In contrast, if adaptation started with ACU stimuli followed by SOM stimuli, almost full CMT occurred. The absolute level of performance achieved after the second or third runs was similar in the VIS and non-VIS conditions. 4. In conclusion, the course of motor learning depends on specific afferent information, and feedforward control has a special influence on the performance only at the onset of the experiment but not on the rate of learning. The fact that little CMT occurs from visual to non-visual stimuli and from ACU to LED suggests that visual afferent input is processed in a different way to non-visual stimuli.

Follow-up study of hysterical psychosis, reactive/psychogenic psychosis, and schizophrenia.

The present study was undertaken to learn more about the longer-term course of nonaffective functional psychoses, including hysterical psychosis. A group of 48 female patients diagnosed with hysterical psychosis, nonhysterical reactive/psychogenic psychosis, and schizophrenia at their first admission were reassessed after an average follow-up period of 11.6 years. Seventy-five percent were receiving outpatient treatment; less than half were on neuroleptics, and only 35% were rehospitalized. The patients suffered from a few, mostly unspecific, symptoms and were relatively well adjusted socially. No differences were found between original diagnostic categories regarding all variables studied. Hysterical psychosis does not appear to be a special clinical entity, distinguishable from other reactive/psychogenic psychoses in the short term and from other nonaffective functional psychoses in the longer term. The symptomatology and clinical presentation of nonaffective functional psychoses at first admission do not allow any prognostic longer-term forecast, and the initial differences between individual psychoses tend to disappear over time.

[Identity measurement with the Frankfurt self concept scales and their relationship to parental bonding]. / Identitätserfassung mit Frankfurter Selbstkonzeptskalen und deren Beziehung zum Parental Bonding.

Psychiatric inpatients and nonpatients were compared using the Frankfurt Self-Concept Scales (FSKN). Firstly, we tried to validate FSKN as a measure of identity using the DSM-III-R identity rating as an external criterion. Then the FSKN ratings of patients and nonpatients were compared. Lastly, we correlated individual FSKN ratings with certain demographic variables, clinical diagnoses, and the two dimensions of the Parental Bonding Instrument (PBI). All FSKN scores of patients with identity disorders differentiated significantly from those without identity disorder, thus confirming FSKN validity. The most significant differences were found in practically all FSKN results comparing patients with nonpatients of both sexes, always in favor of nonpatients. Male patients presented better self-concepts than female patients, whereas practically no significant relationships were found between FSKN scales and sex in nonpatients or between FSKN, vocational category, and diagnosis. Also, the relationship between the scales and age appears to be slight, showing positive in patients and negative in nonpatients. Many significant correlations were found between FSKN scales and PBI dimensions which were negative between the scales and PBI "control" and positive between the scales and PBI "care", both especially in men with regard to their relationship with the father.

Prevalence of extrapyramidal syndromes in psychiatric inpatients and the relationship of clozapine treatment to tardive dyskinesia.

In 200 inpatients on regular neuroleptics, point prevalence of extrapyramidal syndromes, including Parkinson syndrome, akathisia and tardive dyskinesia (TD), was studied and found to be 20, 11 and 22%, respectively. A total of 46 patients have currently, and for a longer time, (average about 3years, median over 1year) been treated with clozapine, and 127 with typical neuroleptics (NLs). Comparing both groups, higher TD scores were found in the clozapine sample. Investigating the influence of a set of seven clinical variables on the TD score with the help of multiple regression analysis, the influence of the treatment modality disappeared, whereas the age proved to be the only significant variable. Studying the role of past clozapine therapy in patients currently on typical NLs and comparing 10 matched pairs of chronic patients with and without TD in whom a complete life-time cumulative dose of NLs was identified, a relationship between TD and length of current typical NL therapy and life-time typical NL dosage could be demonstrated. On the whole, long-term relatively extensive use of clozapine has not markedly reduced the prevalence of extrapyramidal syndromes in our psychiatric inpatient population. In particular, we failed to demonstrate a beneficial effect of clozapine on prevalence of TD. There are certainly patients who suffer from TD in spite of a long-term intensive clozapine treatment.

Level of spinal cord lesion determines locomotor activity in spinal man.

Recent studies have demonstrated that coordinated stepping movements can be induced in patients with complete para-/tetraplegia, when they were standing on a moving treadmill with their body weight partially unloaded and external assistance. The aim of this study was to determine which part of the spinal cord generated the locomotor pattern. In patients with complete paraplegia due to lesions at different levels of the spinal cord, the locomotor pattern was compared with that of healthy subjects. Any similarities in electromyographic (EMG) activity of gastrocnemius and tibialis anterior muscles between the patients and healthy subjects were reflected by the analysis of the variation ratio and amplitudes of the EMG activity. It was found that the higher the level of spinal cord lesion the more "normal" was the locomotor pattern. This suggests that neuronal circuits underlying locomotor "pattern generation" in man are not restricted to any specific level(s) of the spinal cord, but that an intricate neuronal network contributing to bipedal locomotion extends from thoracolumbal to cervical levels.

Identity disturbance in personality disorders.

We explored identity disturbance and some of its correlates and antecedents in patients with personality disorder (PD) pathology. A group of inpatients who all were diagnosed as PD on self-reports were divided as those with (28 patients) and without (62 patients) identity disturbance on the basis of the DSM-III-R borderline PD identity item criterion. The division of the patients was tested and found to be valid. Both groups were compared with each other. Seventy-five percent of patients with and 34% of patients without identity disturbance received the definite interview diagnosis of PD. The syndrome of identity disturbance was encountered in basically all PD types. In contrast, half of all patients with PD presented no identity disturbance. Identity disturbance did not predispose to specific axis I disorders and suicidal behavior, and it was not correlated convincingly with childhood traumatic experiences and parental bonding scores. The results neither support the DSM conceptualization of identity disturbance as an exclusive characteristic of borderline PD, nor the Kernberg's concept of identity disturbance as an essential of borderline personality organization which should be found in almost all PD types.

Locomotor training in paraplegic patients: a new approach to assess changes in leg muscle EMG patterns.

This study describes an amplitude independent assessment of changes in leg muscle EMG patterns in both complete and incomplete paraplegic patients during the course of locomotor training. The approach expresses the change as an approximation of the patients' gait EMG pattern compared with that of healthy subjects. The variation ratio (VR), coefficient of variation (CV) and Pearson's correlation coefficient (R), are used as measures of the dissimilarity/similarity of a set of wave forms. These parameters were evaluated for their ability to assess changes in the EMG pattern of the patients with respect to that of healthy subjects. The VR showed the best correlation to our data and was therefore considered to represent the optimum variable in the assessment of changes in EMG patterns.

Possible antecedents of DSM-III-R personality disorders.

In order to extend our knowledge of the effects of environmental influences upon personality disorder (PD) pathology, childhood traumatic events and parental bonding were studied in 90 PD in-patients of both sexes. Childhood traumatic experiences (primarily physical and/or sexual abuse) and parental bonding dimensions were correlated with PD pathology depending on PD type and cluster. Important differences were found between the sexes. The quality of the paternal relationship (high control, low care) was significantly associated with PD pathology in men, whereas childhood traumatic experiences and the quality of maternal parenting were associated with PD pathology in women. The study of traumatic events such as childhood abuse has recently been the focus of considerable attention. More emphasis in empirical research needs to be given to parental relationships, especially in the case of men.

Two-factor solution of the 20-item Toronto Alexithymia Scale confirmed.

The German version of the 20-item Toronto Alexithymia Scale (TAS-20) was studied in 277 medical students. The factor analysis yielded a two-factor solution, quite in agreement with the results of a recent analysis of the French version of the same scale. The first factor corresponds to the difficulties to identify and to describe feelings, whereas the second factor corresponds to the externally oriented thinking. TAS-20 proved to be a reliable scale to measure alexithymia; the usage of the total scale score is recommended.

Possible correlates of DSM-III-R personality disorders.

An association between personality disorder (PD) pathology, including symptoms of all PD types and Axis I disorders, and suicidal behaviour was studied in a series of 90 non-schizophrenic, non-bipolar in-patients of both sexes without mental retardation or organic brain syndrome. All of these patients, who scored positively on the SCID-II-PQ, were interviewed with the PDE and SCID-P, and with the Structured interview for the study of childhood trauma provided with supplementary items reflecting suicidal behaviour. Mood disorders were found to be significantly correlated with cluster C pathology (PD pathology always being expressed by dimensional PDE scores) and eating disorders were significantly correlated with cluster B pathology in women. Psychoactive substance use disorders were mainly correlated with cluster B pathology and anxiety disorders with cluster C pathology in both sexes. Suicidal behaviour was correlated with PD pathology of all clusters in women, but not in men. In women a strong correlation was found between suicidal behaviour and history of childhood trauma, especially sexual abuse. The results of this study indicate that there is some specificity with regard to the Axis I/Axis II association, more so in relation to PD clusters than in relation to the individual PD types. However, the relationships between PD pathology and Axis I disorders and suicidal behaviour are complex, and they differ between the sexes.

Dissociative experiences and dissociative disorders in acute psychiatric inpatients.

The study attempted to determine the extent of dissociative experiences and the prevalence of dissociative disorders (DDs) in a series of acute psychiatric inpatients and to correlate these experiences and disorders with some sociodemographic, clinical, and historical variables. A total of 207 consecutively admitted psychiatric inpatients qualified for the study. All were examined with the Dissociative Experiences Scale (DES), Structured Clinical Interview for DSM-III-R Personality Questionnaire (SCID-II PQ), Parental Bonding Instrument (PBI), and Frankfurter Self-Concept Scales (FS). Patients who scored greater than 20 on the DES were examined with the Dissociative Disorders interview Schedule (DDIS). Altogether, 20% of patients scored greater than 20 on the DES. In 5% of the patients, a DD was diagnosed. Significant positive correlations were found between DES scores and SCID-II PQ items' frequency with regard to all personality disorder types, especially borderline, antisocial, schizotypal, and dependent. Less pronounced correlations were found between DES and PBI scores, and between DES score and age. Clinical axis I diagnoses did not have any pronounced influence on the DES score. In contrast, patients with greater proneness to dissociation scored lower on most FS scales. There was a tendency for patients with DDs to report childhood abuse more frequently and they complained significantly more of somatic symptoms. Dissociative experiences seem to be as frequent in Swiss as in North American inpatients, whereas DDs (and childhood abuse) were encountered less frequently in Swiss inpatients. A correlation seems to exist between dissociation and somatization.