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At least 1,351 records · Page 75Linked to original sources
PubMed1998

Error-related scalp potentials elicited by hand and foot movements: evidence for an output-independent error-processing system in humans.

The error-related negativity (ERN) is a fronto-centrally distributed component of the event-related brain potential (ERP) that occurs when human subjects make errors in a variety of experimental tasks. In the present study, we recorded ERPs from 128 scalp electrodes while subjects performed a choice reaction time task using either their hands or feet. We applied the brain electric source analysis technique to compare ERNs elicited by hand and foot errors. The scalp distributions of these error potentials suggest that they share the same neural generator and, therefore, that the ERN process is output-independent. Together with other findings, the results are consistent with the hypothesis that the ERN is generated within the anterior cingulate cortex and is elicited by the activation of a generic error-processing system.

Adolescent↗
PubMed2002

Facial reconstruction using the visor scalp flap.

In male burn victims, scar may cause grotesque disfigurement to the upper lip and lower face. There are many ways to address the problem, for simple skin grafting to complex flaps. Bipedicle scalp flaps are used sporadically for reconstruction of the upper lip. In this article, the use of bitemporal artery hair-bearing flap for reconstruction of the moustache and beard area in nine cases as a substitute for facial deformed skin is described. The results indicate that the scalp flap is one of the best-matched flaps for reconstruction of the mid and lower part of the male face. As a result of choosing the proper size of the flap, use of the tissue expander is omitted, the donor site may be closed primarily and early return of the patient to normal life is guaranteed. Although, the width of the flap is not sufficient enough to cover the whole lower face and the cheeks, it is enough to imitate a normal face and give a pleasant appearance.

Adolescent↗
PubMed2003

Dynamics of working memory for moving sounds: an event-related potential and scalp current density study.

Human brain imaging studies have suggested that posterior temporo-parietal regions are involved in auditory spatial processing. We used electroencephalography to investigate the dynamics of temporo-parietal networks during working memory for moving sounds. A delayed matching-to-sample task required a decision on the identity of positions and trajectories of two moving sounds S1 and S2 presented with delays of 927 or 1427 ms. Moving sounds consisted of noise bursts positioned at successive angles to create the impression of one of six possible trajectories at variable spatial positions. Stimuli in the equally difficult control condition were identical to the memory task up to S2, which was replaced by a spatial displacement in the otherwise stationary background sound whose direction had to be detected. Event-related potentials were recorded from 31 scalp electrodes in 15 subjects. Scalp current density estimates allowed to identify the following components. The fronto-central negative variation preceding S2 did not differ between tasks. In contrast, the sustained negative current during the presentation of S1 originating from superior temporal cortex was more pronounced for the memory task, probably reflecting enhanced attention allocation and foreground-background discrimination. Most importantly, the memory task activated current sources over bilateral posterior parietal regions between the middle of S1 and the end of the delay phase. This component was completely absent in the control condition. In summary, the present study disclosed varying degrees of memorization-related, top-down driven influences on the processing of moving sounds at different stages of an auditory network involving temporal and parietal regions.

Acoustic Stimulation↗
PubMed2002

Changes in the scalp topography of event-related potentials and behavioral responses during the sleep onset period.

Event-related potentials (ERPs) and behavioral responsiveness were investigated during the transition from wakefulness to sleep. Ten participants were presented with an auditory oddball task during repeated sleep onset periods. The EEG was recorded from 29 different scalp sites. A 1500-Hz tone pip was presented infrequently (p = .04) within a series of lower pitch 1000-Hz "standard" stimuli (p = .96). Participants were required to button press upon detection of the rare "target" stimulus. During wakefulness, almost all targets were detected. A large amplitude P300 was observed to these detected targets. This P300 was maximum over parietal areas of the scalp. During stage 1 sleep, subjects continued to respond on 47% of trials. The parietal P300 amplitude remained large to these detected targets. It was, however, much attenuated at frontal sites. When the participant failed to detect the target in either stage 1 or 2, no P300 was visible. P300 is thus associated with behavioral detection of the target stimulus, whether in wakefulness or stage 1 "sleep." Trials were also sorted by reaction time (RT), in which bins 1-3 represented increasingly long RT. In the waking state, P300 amplitude did not significantly vary across the different bins. Although mean RT latency varied by 512 ms from bin 1 to bin 3, P300 latency varied by only 25 ms. Differences in RT are thus probably due to response-related processes rather than stimulus classification time.

Acoustic Stimulation↗
PubMed2001

Dermatophyte pseudomycetoma of the scalp: case report and review.

We report the first case of a scalp pseudomycetoma due to Trichophyton schoenleinii in a 15-year-old girl from Senegal. The lesion was not associated with tinea capitis. Long-term antifungal therapy with itraconazole and terbinafine was unsuccessful but a favourable outcome was obtained after surgical removal of the lesion. Between 1973 and 1999, only 12 previous cases of dermatophyte pseudomycetoma of the scalp were reported in the literature. Clinical features and therapeutic outcomes of these cases are reviewed.

Adolescent↗
PubMed2003

Nonsynchronized segmented heterochromia in black scalp hair.

Nonsynchronized segmented heterochromia in black scalp hair is a rarely reported entity, the only previous report being described in association with iron deficiency anaemia. A 14-year-old girl presented with a 2-year history of nonsynchronized segmented heterochromia. She was otherwise well and her serum iron, copper, zinc and protein levels were all within the normal range. She had no clinical evidence of vitiligo or alopecia areata. This patient is believed to represent the first reported case of nonsynchronized segmented heterochromia in black scalp hair as a presentation of premature greying of the hair.

Adolescent↗
PubMed1999

Acquired scalp alopecia. Part II: A review.

The neutrophil-associated and infiltrative scarring alopecias are reviewed including folliculitis decalvans, tufted folliculitis, dissecting cellulitis of the scalp, acne keloidalis and follicular degeneration syndrome. The management of acquired scalp alopecia is also reviewed including newer, promising therapies. More specific agents targeting components of the androgen system will make the treatment of androgenetic alopecia more rewarding. Similarly new immunomodulatory therapies show great promise for the lymphocyte-associated alopecias and include a new generation of macrolide immunosuppressives (tacrolimus, SDZ ASM 981, and SDZ 281-240), some of which appear to have good transcutaneous absorption.

Alopecia↗
PubMed2003

Statistical mapping of scalp-recorded ictal EEG records using wavelet analysis.

PURPOSE: The wavelet transform (WT) is well suited for the analysis of signals whose characteristics vary rapidly over time. We devised a computerized method for objective scoring of scalp-recorded seizures that takes advantage of the WT. METHODS: Using wavelet coefficients as a metric, we devised a statistical scoring method aimed at detecting significant and sustained rhythmic buildup. The approach was used to create spatiotemporal significance maps for each seizure. Each seizure was also independently analyzed by computer and an expert reader not involved in the clinical workup or computer analysis of these patients. Hierarchical decision rules for determining seizure lateralization and localization were established from a training set of seizures and subsequently tested on those from an independent test set of seizures. The test dataset included a total of 57 scalp-recorded seizures from 18 patients, each with a > or =12-month seizure-free surgical outcome. RESULTS: Validation was determined by the site of surgical resection. Of the 57 seizure records in the test dataset, the computerized approach resulted in 48 correctly lateralized seizures as compared to 34 for the expert reader. Further, the computer correctly localized 41 seizures to the expert's 31. CONCLUSIONS: The method presented appears to provide an objective basis for the intrachannel scoring of ictal EEGs with minimal interference from artifacts and intermittent discharges. Although the approach has so far shown a substantial improvement over expert scoring in estimating the lateralization and locus of seizure onset, further testing is required to fully evaluate fully its diagnostic accuracy.

Brain Mapping↗
PubMed2001

Pediatric extragonadal germ cell tumor of the scalp.

Extragonadal germ cell tumors are relatively rare tumors, accounting for 5% to 10% of all germ cell tumors in adults. In children, approximately two thirds of germ cell tumors are extragonadal. Extragonadal germ cell tumor of the scalp is exceedingly rare. The authors report the case of a 1(1/2)-year-old boy with extragonadal germ cell tumor over the occipital region. Examination of the chest, abdomen, and gonads was normal. Computed tomography scan of the head showed a large, well-defined, lobulated, heterogeneously enhancing soft tissue mass lesion in the occipital region. The underlying bone was normal with no evidence of intracranial extension. Biopsy results of the scalp mass showed features consistent with embroynal carcinoma. Serum alpha-fetoprotein (AFP) level was elevated. The child was started on chemotherapy and received 4 cycles of cisplatin, etoposide, and bleomycin (PEB). There was more than 90% reduction in the size of the mass at the end of the fourth cycle. The residual mass was excised and followed up with 2 cycles of postoperative PEB. Ten months after excision the patient is well, without recurrence, and the AFP level is normal.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Disturbance of semantic processing in temporal lobe epilepsy demonstrated with scalp ERPs.

We investigated event-related potentials (N400, LPC and CNV) elicited in temporal lobe epilepsy (TLE) patients and control subjects from scalp electrodes, using a word-pair category matching paradigm. Each prime consisted of a Japanese noun (constructed from 2-4 characters of the Hiragana) followed by a Chinese character (Kanji) as the target, the latter representing one of five semantic categories. There were two equally probable target conditions: match or mismatch. Each target was preceded by a prime, either belonging to, or not belonging to, the same semantic category. The subjects were required to respond with a specified button press to the given target, according to the condition. We found RTs to be longer under the mismatch condition in both subject groups. The N400 amplitude was reduced in TLE subjects under both conditions, although LPC and CNV amplitudes showed no significant differences. These results suggest that scalp N400 is capable of demonstrating disturbance of semantic processing in TLE non-invasively.

Adult↗
PubMed2001

The PUVA-turban as a new option of applying a dilute psoralen solution selectively to the scalp of patients with alopecia areata.

BACKGROUND: Alopecia areata is a burden for many patients and often resistant, even to extensive therapy. Orally administered PUVA therapy has been shown among numerous systemic and topical treatment modalities to be a therapeutic alternative. However, the clinical use of oral PUVA is often limited by systemic side effects. Bath-PUVA therapy offers an alternative solution because of the negligible systemic absorption of psoralen with this technique. Through use of a "PUVA-turban" it is now possible to administer a dilute bathwater solution containing 8-methoxypsoralen (8-MOP) to the scalp. OBJECTIVE: The purpose of this study was to determine whether PUVA turban therapy is effective in treating alopecia areata in different clinical stages. METHODS: We treated 9 patients with severe, rapidly progressing, treatment-resistant alopecia areata with PUVA-turban treatment as a modification of bath-PUVA therapy. At each treatment session a cotton towel was soaked with a 0.0001% 8-MOP solution (1 mg/L) at 37 degrees C, wrung gently to remove excess water, and wrapped around the patient's head in a turban fashion for 20 minutes. This was directly followed by UVA radiation. Treatment sessions were initially performed 3 to 4 times per week. RESULTS: The cumulative UVA doses given over treatment periods of up to 24 weeks were 60.9 to 178.2 J/cm(2), with single doses ranging from 0.3 to 8.0 J/cm(2). After up to 10 weeks of treatment, hair regrowth could be noticed in 6 of 9 patients. Two patients did not respond to the treatment, and one patient showed only vellus hair regrowth. CONCLUSION: PUVA-turban therapy can be considered a useful method of administering a dilute psoralen solution selectively to the scalp of patients. It has been shown to be a well-tolerated and, in some patients, efficient therapeutic alternative in the treatment of alopecia areata.

Administration, Topical↗
PubMed2002

Human scalp recorded sigma activity is modulated by slow EEG oscillations during deep sleep.

The EEG during deep sleep exhibits a distinct cortically generated slow oscillation of around and below 1 Hz which can be distinguished from other delta (0.5-3.5 Hz) activity. Intracranial studies showed that this slow oscillation triggers and groups cortical network firing. In the present study, we examined whether the phases of the slow oscillation during sleep stage 4 are correlated with the magnitude of sigma (12-16 Hz) and gamma (> 20 Hz) scalp activity. For this purpose, 10-min segments of uninterrupted stage 4 sleep EEG from 9 subjects were analyzed by applying wavelet techniques. We found that scalp recorded sigma, but not gamma, activity is modulated by the phases of the slow oscillation during deep sleep. Enhancement of sigma activity was observed to be triggered by the peak of the surface positive slow wave component, whereas reduction of sigma activity started around the peak of the negative component.

Adult↗
PubMedDate not supplied

Genetic basis of human scalp hair weight: a twin study.

Human scalp hair weight has been measured in 48 pairs of German twins of known zygosity. Variance analysis indicates a strong genetic component in variability in human scalp hair weight. No sex variation upon the character is found.

Adolescent↗
PubMed2004

Adaptive autoregressive identification with spectral power decomposition for studying movement-related activity in scalp EEG signals and basal ganglia local field potentials.

We propose a method that combines adaptive autoregressive (AAR) identification and spectral power decomposition for the study of movement-related spectral changes in scalp EEG signals and basal ganglia local field potentials (LFPs). This approach introduces the concept of movement-related poles, allowing one to study not only the classical event-related desynchronizations (ERD) and synchronizations (ERS), which correspond to modulations of power, but also event-related modulations of frequency. We applied the method to analyze movement-related EEG signals and LFPs contemporarily recorded from the sensorimotor cortex, the globus pallidus internus (GPi) and the subthalamic nucleus (STN) in a patient with Parkinson's disease who underwent stereotactic neurosurgery for the implant of deep brain stimulation (DBS) electrodes. In the AAR identification we compared the whale and the exponential forgetting factors, showing that the whale forgetting provides a better disturbance rejection and it is therefore more suitable to investigate movement-related brain activity. Movement-related power modulations were consistent with previous studies. In addition, movement-related frequency modulations were observed from both scalp EEG signals and basal ganglia LFPs. The method therefore represents an effective approach to the study of movement-related brain activity.

Algorithms↗
PubMed1986

Adriamycin alopecia prevented by cold air scalp cooling.

Preliminary studies are reported on the effectiveness of cold air scalp cooling to prevent alopecia in patients receiving Adriamycin. Cold air produced in a novel way using a vortex refrigeration tube was applied to the scalp for 15 min before and 30 min after the administration of Adriamycin and other cytotoxic agents. Sixteen of 26 patients had no hair loss, four had slight hair loss, and six required a wig. Two subgroups fared particularly well. Four of four patients treated with ABVD for Hodgkin's disease and nine of 13 treated with Adriamycin (40 mg/m2) and vincristine (2 mg) for breast cancer had no hair loss.

Air Movements↗
PubMed1997

Aplasia of the vertex without scalp defect.

We report a case of an extremely rare craniofacial condition, which, to our knowledge, has previously been reported once only. A male infant presented with a giant congenital bone defect of the skull, in the vertex region (10 x 20 cm) and without scalp deficiency. Minimal turricephaly and moderate orbital hypertelorism were associated with slight limb abnormalities, but psychometrical assessments appeared normal. Nonsurgical treatment was initially decided upon, but spontaneous reossification was so moderate that skull reconstruction was carried out at 28 months of age because of the risk of trauma. A full-size resin cephalic skeletal reconstruction was obtained according to three-dimensional computed tomography using stereolithographic techniques. A titanium plate was customized on the resin model for ideal adaptation to the convex skull defect (8 x 16 cm). Surgery was simply performed, consisting of a preliminary undermining between the dura mater and the scalp and screwing of the custom titanium plate. The initial follow-up was uneventful.

Bone Plates↗
PubMed1991

Topography of scalp-recorded motor potentials in human finger movements.

Four distinct negative events were identified in the averaged, scalp-recorded EEGs of normal subjects before and after the onset of self-paced, voluntary finger movements; reaction-time movements and passive movements were also studied. These events are the peak of the negative slope (NS'), the initial slope of motor potential (isMP), the parietal peak of motor potential (ppMP), and the frontal peak of motor potential (fpMP). For self-paced movements, NS' and isMP occurred before the onset of electromyographic (EMG) activity, and ppMP and fpMP occurred after the onset of EMG activity. NS' had a wide distribution, covering the parietal region with slight contralateral predominance. The isMP mapped focally over the contralateral hand motor area on the scalp. The location of ppMP was similar to that of isMP. The fpMP was localized anterior and medial to motor cortex with a contralateral preponderance and possible location over the supplementary motor area. The isMP and fpMP also were identified in the recordings of reaction-time movements, but only the fpMP persisted in the recordings of passive movements. The isMP appears to reflect activation of the cortical cells in the hand area of motor cortex for the execution of voluntary movement, and the fpMP appears to reflect proprioceptive feedback from the periphery.

Adult↗