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Biomedical subjects

P Kropp

Publications and source records attributed to P Kropp.

At least 37 records · Page 2Linked to original sources
PubMed2000

Slow cortical potentials in migraine families.

Amplitude and habituation of event-related potentials are abnormal in migraine. We investigated 43 migraine and 41 healthy families to evaluate the influences of age, sex and familial contribution on the variance of amplitude and habituation of the contingent negative variation (CNV). Analysis of individual differences in relation to the CNV habituation was performed. The study demonstrated that habituation of the early CNV component characterizes migraine considerably better than the CNV amplitudes. Habituation, however, is strongly influenced by age. Migraine adults and children generally showed reduced habituation. Surprisingly, more than 30% of the healthy adults demonstrated a marked loss of habituation. The reduced CNV habituation represented a high sensitivity but low specificity to migraine, especially in children. CNV amplitude and habituation parameters revealed a considerable familial contribution associated with migraine. No familial influence on either morphology or habituation of the CNV in healthy families or between healthy members of migraine families was observed. The low specificity and familial transmission of CNV parameters in members of migraine families suggest that increased amplitudes and reduced habituation of CNV do not constitute a primary risk factor for migraine, but rather represent a predisposition. Genetic components probably affect variation of the CNV amplitude and habituation.

Adolescent↗
PubMed2000

[Prediction of verbal and numerical comprehension in patients with cochlear implants].

BACKGROUND: Cognitive abilities determine the outcome of cochlear implantation. Neuropsychological tests of intellectual, memory, attentional and emotional functions were applied pre-operatively in 33 deaf patients receiving a cochlear implant. The outcome of verbal and numerical comprehension was measured in a subgroup of 14 patients post-operatively and correlated with pre-operative neuropsychological performance. METHODS: Neuropsychological performance was recorded using standardized tests for intellectual abilities (abbreviated Wechsler Adult Intelligence Scale [WAIS], crystallized intelligence scale), memory performance (Benton Visual Retention Test), attentional functions (d2 letter-cancellation-test), reaction time (Vienna Reaction Test) and emotional state (personality inventories). Verbal and numerical comprehension was measured post-operatively following adaptation of the speech processor. Performance and comprehension data were correlated. RESULTS: Cognitive performance parameters did not differ significantly from those of a healthy group. There was a correlation of r = +0.65 between numerical comprehension and the "mosaic-test", a subtest of the WAIS and of r = +0.78 between numerical comprehension and the crystallized intelligence scale. CONCLUSIONS: Pre-operative cognitive parameters may predict the outcome of cochlear implants.

Adolescent↗
PubMed2000

Contingent negative variation as indicator of duration of migraine disease.

Amplitudes of early wave contingent negative variation (iCNV) reveal significant differences between migraine patients and healthy controls, indicating a lack of habituation and pronounced attentional functions in migraine patients. CNV amplitudes were recorded in 20 migraine patients. The CNV amplitudes were Pearson correlated with the individual duration of the migraine disease. Only iCNV correlates inversely with the duration (r = -.544). The data show an influence of duration of migraine disease on iCNV amplitudes. It is suggested that iCNV is an indicator of chronicity in persistent migraine.

Adult↗
PubMed1999

Migraine--evidence for a disturbance of cerebral maturation in man?

The contingent negative variation (CNV), a slow cortical potential between two defined stimuli, was used to record the effect of age in 162 migraine patients and 320 healthy controls aged between 8 and 59 years. The early component (iCNV) and habituation slope of 32 GO-trials are presented. There were no significant differences between healthy controls and migraine patients in iCNV amplitudes or habituation slope up to the age of 19 years. In the age groups from 20-59 years the healthy controls showed a significantly reduced iCNV compared with migraine patients and healthy controls below 20 years of age. While the habituation slope increased in healthy controls, there was no habituation of iCNV in migraine patients. It is suggested that reduced iCNV amplitudes in healthy controls indicate a state of cerebral maturation. This maturation effect is missing in adult migraine patients, leading to pronounced attentional effort in these patients.

Adolescent↗
PubMed1999

Contingent negative variation indicates phasic arousal for externally cued unilateral eye blink in human subjects.

The contingent negative variation (CNV) as a slow cortical potential was used to investigate cortical processing of externally cued, voluntary unilateral eye blink. Probands blinked as a response within a modified two-stimulus reaction time paradigm. Reaction time and amplitudes of CNV were determined. The activity of the orbicularis oculi muscles (OO) was registered by surface electromyography (EMG). Probands who performed unilateral eye blinks with accurately inhibiting contralateral OO activity showed a significantly higher negativity of the early CNV component compared with the bilateral eye blink condition. This effect was confined to the beginning of unilateral blinking performance. It is suggested that the unilateral eye blink is a challenging motor task, initially requiring an increased cortically driven arousal and attention as revealed by increased early CNV components.

Adult↗
PubMed1999

Vascular dementia versus dementia of Alzheimer's type: do they have differential effects on caregivers' burden?

OBJECTIVES: We investigated homecare patients with dementia of Alzheimer's type (DAT; n = 36) or vascular dementia (VD; n = 36) and their care-providing relatives regarding clinical and psychosocial variables to determine whether DAT and VD impose different burdens on caregivers. METHOD: All patients were diagnosed according to ICD-10 criteria. The diagnoses were confirmed by internal medical, clinical-neurological, and psychiatric parameters. The severity of the dementias was graded according to the Global Deterioration Scale (GDS). Caregiving relatives responded to the Behavioral Pathology in Alzheimer's Disease Rating Scale (BAD), the Blessed Dementia Scale (BDS), and the Screen for Caregiver Burden (SCB). RESULTS: Analyses revealed that caregivers' burden (SCB), disease symptoms and personality changes of patients (BAD), and the patients' inability to cope with everyday tasks (BDS) were sharply higher for DAT than for VD patients in the group with severe dementia. Concerning patients with mild or moderately severe disease, scores in the DAT group were similar or lower than those in the VD group. CONCLUSION: In early stages, VD patients impose a greater burden on relatives than do patients with DAT. In severe stages this relationship undergoes a reversal, with relatives of DAT patients experiencing the burden more adversely than those of VD patients. The differences in the onset and course characteristics, as well as the specific differences between these two types of dementia with respect to caregiver burden factors, call for their diagnostic separation and the development of specific homecare support systems for family caregivers.

Activities of Daily Living↗
PubMed1999

Slow cortical potentials in migraine: a comparison of adults and children.

Amplitudes of contingent negative variation (CNV) in 40 migraine patients were studied during the pain-free period and compared with healthy controls (n = 24). The early component (initial CNV) is especially more negative in migraine patients. Within the migraine group, 14 children with migraine without aura (mean age 13.6 years) were compared with 11 healthy children (mean age 12.4 years). Migraine children differ from healthy children in the same manner that adult migraine patients differ from healthy adults. The CNV of five healthy children did not differ from the CNV of their siblings suffering from migraine. We suggest that there is a family-related cortical hypersensitivity which does not necessarily lead to the development of migraine.

Adolescent↗
PubMed1998

Prediction of migraine attacks using a slow cortical potential, the contingent negative variation.

Amplitudes of contingent negative variation (CNV) as a slow cortical potential in migraine patients were recorded before and after migraine attacks. The level of CNV amplitudes, especially of the early component, showed a trend in rise of negativity 1 day before the attack, whereas amplitudes were normal for 2-3 days following an attack. In most cases the attack occurred when the CNV amplitude showed maximum negativity. We conclude that migraine-susceptible days are indicated by a high CNV amplitude the day before the attack.

Adult↗
PubMed1998

Contingent negative variation in patients with chronic daily headache.

The aim of this study was the investigation of amplitude and habituation of contingent negative variation (CNV) in migraine and chronic daily headache (CDH) patients in order to describe possible neurophysiological features responsible for the clinical transformation and worsening of the headache. Fifteen females suffering from migraine without aura and 15 females diagnosed with CDH evolved from migraine without aura with interparoxysmal chronic tension-type headache (transformed migraine), underwent CNV recording. Fifteen healthy females matched for age served as controls. CNV was obtained from C3 and C4 using the standard reaction time paradigm and 3 sec ISI. The amplitudes and habituation of total CNV, early and late components, and of post-imperative negative variation (PINV) were calculated. The migraine patients were characterized by significantly more pronounced negativity of the early component and total CNV, compared to CDH sufferers and controls. CDH patients demonstrated significantly reduced negativity of the late component and pronounced PINV compared to the other groups. The early component of CNV did not habituate in migraine or CDH patients. However, the impaired habituation in CDH was related to significantly lower amplitudes. These results support the diagnostic and scientific value of habituation in migraine research and therapy. Late components of CNV and PINV can be considered as predictive variables for transformation of migraine. The results are discussed in terms of the relationship between late CNV, PINV, environment control abilities and susceptibility for development of depression.

Adaptation, Psychological↗
PubMed1996

[Exteroceptive suppression of activity of the temporal muscle in analysis of pain mechanisms].

Stimulating afferent fibers of the trigeminal nerve usually causes two successive suppressions (ES1 and ES2) of the voluntary muscle activity of chewing muscles. The first phase of decreased voluntary activity is called the early exteroceptive suppression period (ES1); the second phase is called the late exteroceptive suppression period (ES2). Between these two suppression periods is a phase of increased muscle activity, the so-called facilitation period (FP). Usually, in healthy subjects this normal pattern of exteroceptive suppression can be elicited regularly. The reflex answer may occur at low non-painful stimulus intensities; however, typically it appears to be most pronounced with high-intensity stimuli. Because of the obvious relationship between stimulus intensity, pain perception and reflex answer, the reflex is regarded as an antinociceptive reaction. Chronic pain syndromes like chronic tension-type headache and migraine without aura cause changes within the normal ES recording pattern. Furthermore, some substances used in pain therapy such as serotoninagonists or antagonists, acetylsalicylic acid or naloxon may also alter the general appearance of the ES. In this review different parameters that influence the ES reflex answer are summarized. Above, the diagnostic value of the changes of the ES for pathophysiological procedures regarding pain perception and pain processing in certain pain diseases is discussed.

English Abstract↗
PubMed1996

[Electrophysiological studies on headache: the contingent negative variation].

The contingent negative variation (CNV) is a slow cortical potential recorded from the scalp. This method allows the pathophysiology of chronic headaches to be elucidated. When assessed during the pain-free interval patients suffering from migraine without aura show significantly more negative amplitudes than healthy controls. This negativity reflects the activity of cerebral noradrenergic systems. Some studies using repeated recordings of the CNV show a periodicity in amplitude change. When migraine patients are assessed a few days before a migraine attack occurs, they show pronounced negativity, which normalized during the attack. Despite these interesting findings that are based on group comparisons, evaluating the CNV on an individual basis does not allow specific conclusions. Thus, assessment of the CNV is an important tool to examine pathophysiological aspects of chronic headaches, but is not suitable as a diagnostic procedure.

English Abstract↗
PubMed1995

Contingent negative variation during migraine attack and interval: evidence for normalization of slow cortical potentials during the attack.

The contingent negative variation (CNV) amplitudes of 16 subjects with migraine without aura were studied during pain-free intervals and during attacks and the results were compared with those of 22 healthy subjects. In 32 trials the CNV amplitudes were calculated for (a) "total interval", (b) "early CNV component", (c) "late CNV component", and (d) habituation. There was a significantly higher total CNV amplitude in migraine subjects during pain-free intervals compared to that of the healthy subjects and migraine patients during an attack. Healthy subjects as well as subjects studied during the attack showed a significant habituation whereas migraine subjects studied during pain-free intervals did not. This suggests that the higher CNV amplitude in migraine patients studied between pain-free attacks may be due in part to impaired habituation.

Adult↗
PubMed1993

Contingent negative variation--findings and perspectives in migraine.

Contingent negative variation (CNV) is a negative cerebral potential which is related to attention and arousal. CNV occurs during an experimental situation in which stimuli and responses are serially organized. Between attacks migraine patients have on average higher negative amplitudes compared to healthy controls or patients with tension-type headache. Successful treatment with beta-blocking agents decreases CNV amplitudes. In spite of encouraging findings in neurological disorders, CNV is not widely used. In this review some possible reasons for this are pointed out.

Brain↗
PubMed1993

Is increased amplitude of contingent negative variation in migraine due to cortical hyperactivity or to reduced habituation?

The aim of this study was to compare the habituation kinetics of contingent negative variation (CNV) between 12 migraineurs without aura and matched healthy controls. CNV was studied with a 3 sec interval between the warning stimulus (WS) and the imperative stimulus (IS). The data from (a) the total interval (WS-IS), (b) early component, and (c) late component were analyzed. During successive trials the habituation kinetics were determined using regression analysis. On CNV averaged over 32 trials, migraine patients had a significantly higher negativity in the total interval compared to controls. When sequential blocks of four trials were analyzed, the most significant finding in migraineurs was lack of habituation of the early CNV component. The present study indicates that a delayed habituation, rather than a general increased cortical activity, is responsible for the CNV abnormalities in migraine without aura. We suggest that migraineurs between attacks not only have a cortical hyperexcitability, but also a lack of cortical inhibition causing delayed habituation.

Acoustic Stimulation↗
PubMed1993

Exteroceptive silent periods of temporalis muscle activity: correlation with neuropsychological findings.

The latency and duration of the early (ES 1) and late (ES 2) exteroceptive silent period of temporalis muscle activity were determined in 51 neurological patients. We investigated whether these electrophysiological parameters correlated with neuropsychological variables of the patients using standardized scores for personality index, state of well-being and physical symptoms. There were no correlations between personality traits and the electrophysiological parameters, while we found significant correlations between the duration of ES 2 and momentary psychological and physical well-being variables. Moreover, the score of the momentary well-being item 'general feeling of well-being' was demonstrated to moderate significantly the ES 2 duration (P = 0.018). Therefore, neuropsychological factors prove to be of great relevance to the exteroceptive silent periods of temporalis muscle activity.

Adolescent↗