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PubMedDate not supplied

Fetal scalp blood sampling.

Fetal scalp blood sampling (FSBS), in conjunction with fetal heart rate monitoring, is a method of fetal surveillance that may avoid cesarean delivery of the healthy fetus or indicate the need for immediate delivery of a compromised fetus. Some researchers have recently begun to question the efficacy of FSBS. In this article, three nurse-midwives discuss FSBS as a tool in assessing fetal well-being during labor and consider whether FSBS is a nurse-midwifery procedure.

Blood Gas Analysis↗
PubMed1987

Scalp-recorded short and middle latency peroneal somatosensory evoked potentials in normals: comparison with peroneal and median nerve SEPs in patients with unilateral hemispheric lesions.

Peroneal somatosensory evoked potentials (SEPs) were performed on 23 normal subjects and 9 selected patients with unilateral hemispheric lesions involving somatosensory pathways. Recording obtained from right and left peroneal nerve (PN) stimulations were compared in all subjects, using open and restricted frequency bandpass filters. Restricted filter (100-3000 Hz) and linked ear reference (A1-A2) enhanced the detection of short latency potentials (P1, P2, N1 with mean peak latency of 17.72, 21.07, 24.09) recorded from scalp electrodes over primary sensory cortex regions. Patients with lesions in the parietal cortex and adjacent subcortical areas demonstrated low amplitude and poorly formed short latency peroneal potentials, and absence of components beyond P3 peak with mean latency of 28.06 msec. In these patients, recordings to right and left median nerve (MN) stimulation showed absence or distorted components subsequent to N1 (N18) potential. These observations suggest that components subsequent to P3 potential in response to PN stimulation, and subsequent to N18 potential in response to MN stimulation, are generated in the parietal cortical regions.

Adult↗
PubMedDate not supplied

Normative data on scalp responses evoked by infraorbital nerve stimulation.

Normative data concerning the waves W1, W2, W3, P4, N5, P6 and N7 recorded from the scalp after stimulation of the infraorbital nerve have been collected from 96 healthy subjects, selected according to age and sex. Peak latency, inter-peak intervals, side-to-side asymmetry of inter-peak intervals, amplitude, amplitude ratio of some components versus W1 and side-to-side asymmetry of such ratio have been analysed as functions of age and sex. None of these parameters appeared to be affected by sex; computation of the correlation coefficient showed a significant (P less than 0.01), though slight, increase of value of the inter-peak intervals W1-W2 and W1-W3 with age. This increase was partially confirmed by analysis of variance. However, such differences are too small to be useful for practical applications, so only a single normative value is proposed for each parameter. The influence of stimulus strength on the amplitude of the W1 component has been studied in 10 more subjects; amplitude saturation of this wave has been found to take place at intensities between 4 and 6 times the sensory threshold. Increasing the stimulus rate from 1 to 3 pulses/sec did not affect any of the components. It is remarked that components W1, W2, W3 and, to a lesser extent, P4 are the ones to be considered useful in clinical practice.

Adult↗
PubMedDate not supplied

Early scalp responses evoked by stimulation of the supraorbital nerve in man.

In 25 healthy volunteers the supraorbital nerve was stimulated and evoked potentials were recorded. Leads were placed on the scalp and along the ipsilateral eyebrow-mastoid line and were either referred to a non-cephalic reference (on the neck, or Cv7) or linked to form bipolar derivations. As template wave form was chosen the one obtained from derivation Cz-Cv7, which had an initial triphasic component with negative (SW1a), positive (SW1b), negative (SW1c) polarity (mean latencies 0.63, 0.95 and 1.43 msec), followed by 2 negative waves (SW2 and SW3, mean latencies of 2.20 and 2.89 msec). A final positive wave could be observed in most cases (SP4, mean latency of 4.08 msec). The records collected from the various derivations showed that each component (SW1, SW2, SW3 and SP4) had a different behaviour, thus suggesting separate origins. SW1 would originate from a volley travelling from the point of stimulation towards the mastoid, probably across the ophthalmic branch of the trigeminal nerve. The subsequent components would be generated by deeply situated structures: double pulse stimulation suggests that SW1, SW2 and SW3 are generated before the first synapse, whereas SP4 is a postsynaptic event. A strong similarity exists between the components evoked by stimulation of the supraorbital and the infraorbital nerves. Local anaesthetic block of the frontal nerve on the stimulated side and monitoring of the EMG activity of m. orbicularis oculi and m. frontalis ruled out any muscle contamination of the responses described in this paper.

Adult↗
PubMedDate not supplied

Direct recording of somatosensory evoked potentials in the vicinity of the dorsal column nuclei in man: their generator mechanisms and contribution to the scalp far-field potentials.

Somatosensory evoked potentials (SEPs) in the vicinity of the dorsal column nuclei in response to electrical stimulation of the median nerve (MN) and posterior tibial nerve (PTN) were studied by analyzing the wave forms, topographical distribution, effects of higher rates of stimulation and correlation with components of the scalp-recorded SEPs. Recordings were done on 4 patients with spasmodic torticollis during neurosurgical operations for microvascular decompression of the eleventh nerve. The dorsal column SEPs to MN stimulation (MN-SEPs) were characterized by a major negative wave (N1; 13 msec in mean latency), preceded by a small positivity (P1) and followed by a large positive wave (P2). Similar wave forms (P1'-N1'-P2') were obtained with stimulation of PTN (PTN-SEPs), with a mean latency of N1' being 28 msec. Maximal potentials of MN-SEPs and PTN-SEPs were located in the vicinity of the ipsilateral cuneate and gracile nuclei, respectively, at a level slightly caudal to the nuclei. The latencies of P1 and N1 increased progressively at more rostral cervical cord segments and medulla, but that of P2 did not. A higher rate of stimulation (16 Hz) caused no effects on P1 and N1, while it markedly attenuated the P2 component. These findings suggest that P1 and N1 of MN-SEPs, as well as P1' and N1' of PTN-SEPs, are generated by the dorsal column fibers, and P2 and P2' are possibly of postsynaptic origin in the respective dorsal column nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Temporal correspondence of intracranial, cochlear and scalp-recorded human auditory nerve action potentials.

Conventional, vertex-ipsilateral ear records ('A'), as well as 3-channel Lissajous' trajectories (3-CLTs) of auditory brain-stem evoked potentials (ABEPs) were recorded from the scalp simultaneously with tympanic membrane electrocochleograms ('TME') and auditory nerve compound action potentials ('8-AP') recorded intracranially using a wick electrode on the auditory nerve between the internal auditory meatus and the brain-stem. The recordings were made during surgical procedures exposing the auditory nerve. The peak latency recorded from 'TME' corresponded to trajectory amplitude peak 'a' of 3-CLT and to peak 'I' of the 'A' channel ABEP. Peak latency of '8-AP' was slightly longer than the latency of peak 'II' of 'A' when '8-AP' was recorded from the root entry zone and the same or shorter when recorded from the nerve trunk. '8-AP' peak latency was shorter than trajectory amplitude peak 'b' of 3-CLT regardless of where the wick electrode was along the nerve. Peak latencies from all recording sites clustered into two distinct groups--those that included N1 from 'TME,' peak 'I' of the 'A' record and trajectory amplitude peak 'a' of 3-CLT, and those that included the negative peak of '8-AP' and trajectory amplitude peak 'b' of 3-CLT, as well as peak 'II' of the 'A' record, when present. In one case, the latency of peak 'II' and trajectory amplitude peak 'b' was manipulated by changing the conductive properties of the medium surrounding the auditory nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1994

Dissociation of temporal and frontal components in the human auditory N1 wave: a scalp current density and dipole model analysis.

This study reports a combined scalp current density (SCD) and dipole model analysis of the N1 wave of the auditory event-related potentials evoked by 1 kHz tone bursts delivered every second. The SCD distributions revealed: (i) a sink and a source of current reversing in polarity at the inferotemporal level of each hemiscalp, compatible with neural generators in and around the supratemporal plane of the auditory cortex, as previously reported; and (ii) bilateral current sinks over frontal areas. Consistently, dynamic dipole model analysis showed that generators in and outside the auditory cortex are necessary to account for the observed current fields between 65 and 140 msec post stimulus. The frontal currents could originate from the motor cortex, the supplementary motor area and/or the cingulate gyrus. The dissociation of an exogenous, obligatory frontal component from the sensory-specific response in the auditory N1 suggests that parallel processes served by distinct neural systems are activated during acoustic stimulation. Implications for recent models of auditory processing are discussed.

Adult↗
PubMed1991

Buschke-Ollendorff syndrome of the scalp: histologic and ultrastructural findings.

Buschke-Ollendorff syndrome is an association of connective tissue nevi and osteopoikilosis that usually appears in the first decades of life. The nevi occur on the trunk and extremities. In a 48-year-old man with this rare syndrome the connective tissue nevus was located on the scalp and was pruritic. Histologically, involvement of the epidermis with cystic dilatation of the hair follicles and an abnormality of mucopolysaccharides were present. The nevi in this syndrome may involve an alteration in the three components of connective tissue to a variable degree.

Collagen↗
PubMed1991

Nodular cutaneous B-cell lymphoma of the scalp in the acquired immunodeficiency syndrome.

Aggressive B-cell non-Hodgkin's lymphoma frequently complicates human immunodeficiency virus type 1 infection. Although extranodal disease is an important feature of this condition, the incidence of cutaneous involvement has not been determined. A review of 754 published cases of B-cell non-Hodgkin's lymphoma associated with human immunodeficiency virus type 1 revealed an incidence of cutaneous extranodal involvement of 8.2%, approximately equal to that seen in non-Hodgkin's lymphoma not associated with human immunodeficiency virus. Lymphoma was the initial manifestation of acquired immunodeficiency syndrome in two thirds of these cases. In particular, although the head and neck are commonly involved in non-Hodgkin's lymphoma not associated with human immunodeficiency virus, scalp involvement is uncommon in human immunodeficiency virus-associated B-cell non-Hodgkin's lymphoma, and we report the second case. The natural history and proposed pathogenesis of human immunodeficiency virus-associated non-Hodgkin's lymphoma are discussed.

Antineoplastic Agents↗
PubMed1992

Ectodermal dysplasias associated with clefting: significance of scalp dermatitis.

Several clinical syndromes are characterized by ectodermal dysplasia (ED) in association with clefting of the lip and/or palate. The three most commonly recognized entities are (1) the EEC syndrome (ectodermal dysplasia, ectrodactyly, cleft lip/palate); (2) the Rapp-Hodgkin syndrome with ectodermal dysplasia, cleft lip/palate, and mid facial hypoplasia; and (3) the Hay-Wells or AEC syndrome (ankyloblepharon, ectodermal defects, cleft lip/palate). The clinical characteristics of these entities as well as several less common syndromes are reviewed and summarized. The presence of scalp dermatitis in patients with the AEC syndrome and less often the Rapp-Hodgkin syndrome is emphasized.

Cleft Lip↗
PubMed1981

Life-span change in visually evoked potentials at central scalp.

Three intensities of patterned flash were used to elicit visually evoked potentials (VEPs) from central scalp of 220 healthy males aged 4-90 years. Intensities were based on visual thresholds. VEP components from children and oldsters were generally larger than those of subjects of intermediate ages and, in response to increased flash intensity, demonstrated greater amplitude enhancement. This pattern of age changes is thought to reflect decreased cortical inhibition in the young and the old with inhibitory capacity being maximal during late adolescent and early adult years. Hemispheric asymmetries were observed. VEP amplitudes from the right hemisphere were larger than those from the left and demonstrated a greater amplitude augmentation to brighter flashes.

Adolescent↗
PubMed1992

Dermatofibrosarcoma protuberans of the scalp.

Dermatofibrosarcoma protuberans is an uncommon tumour of the dermis and rarely occurs on the scalp; there are few known predisposing factors. A case is described of such a tumour that occurred at the site of radiotherapy for a basal cell carcinoma. Histological characteristics, behaviour and management of dermatofibrosarcoma protuberans are discussed.

Aged↗
PubMed1984

In vivo induction of aryl hydrocarbon hydroxylase in human scalp hair follicles by topical application of a commercial coal tar preparation.

Five low-dose applications of a commercial coal tar preparation on a small scalp skin region resulted in an induction of aryl hydrocarbon hydroxylase (AHH) activity in freshly isolated human hair follicles. Large but reproducible interindividual differences in AHH-inducibility could be detected. The method offers the opportunity to measure AHH-inducibility, which has been correlated to the risk of developing chemical-induced cancer, in vivo in normal epithelium, a cell-type highly relevant for chemical carcinogenesis. Smoking habits did not have any effect on AHH-activity in freshly isolated hair follicles. Therefore the method potentially permits the identification of persons with high and low genetically determined AHH-inducibility.

Administration, Topical↗
PubMed1981

The use of kainic acid for studying the origins of scalp-recorded auditory brainstem responses in the guinea pig.

Kainic acid was injected into the medial nucleus of the trapezoid body (MNTB) of guinea pigs to evaluate its use in studying generator loci of the scalp-recorded auditory brain stem response (ABR). Sound-evoked near-field potentials from the MNTB and far-field ABRs were recorded before, during and up to 2 h after the injections. Two hours post-injection, small amounts of kainic acid (0.25 nmol in 0.1 microliters of Ringer solution) resulted in neuronal destruction which histologically appeared confined to the MNTB. Larger amounts (10 nmol in 1.0 microliters) produced more extensive lesions. Regardless of the dose of kainic acid, near-field activity evoked by contralateral ear stimulation was almost totally abolished and ABR wave III amplitude was reduced by as much as 60%. In future studies, the use of excitotoxic amino acids to produce lesions within complex nuclear subdivisions of the auditory pathway may yield valuable information as to the relative contributions that brainstem structures make to the various waves comprising the ABR and about the behavioral effects that axon sparing lesions produce.

Acoustic Stimulation↗
PubMed1995

Somatosensory evoked magnetic fields after mechanical stimulation of the scalp in humans.

Somatosensory evoked magnetic fields after mechanical stimulation by air-pressure-induced tapping which was applied to the forehead and occiput were examined in normal human subjects. The equivalent current dipole (ECD) of the initial magnetic field, 1M, was identified in the primary somatosensory cortex (SI) in the hemisphere contralateral to the stimulation. The ECD of the subsequent magnetic fields, 2M, was identified in bilateral second sensory cortices (SII). The ECD position of 1M in SI generated after the scalp stimulation was closely inferior to the hand area of the SI, which was consistent with the well-known somatotopic organization, 'homunculus'.

Adult↗
PubMed1987

Deep electrical burns to the scalp.

Full skin thickness burns to the scalp involving bone damage are not uncommon. These are mainly caused by electricity, but there are some flame injuries. Investigation of the extent of bone damage by technetium bone scan and the use of CT head scan are recommended. Early closure of the defect using a flap is also recommended, even if wound contamination is present. The results can be very gratifying.

Adult↗