Biomedical subjects
Publications and source records attributed to E J Colon.
Three patients, two males of 37 and 38 years and one female of 23 years, committed arson inspired by complicated psychiatric problems. They did not meet the specific diagnostic criteria of pyromania. Arson as a rule is not the same thing as pyromania.
Few studies have addressed the issue of nursing students with learning disabilities, although students with both identified and undiagnosed learning disabilities are pursuing nursing education. Legal mandates concerning these students impact nursing programs and faculty. To reduce the risk of discrimination litigation, nursing education programs need to establish educational strategies to promote these students' success. The purpose of this research was to discover the extent to which Bachelor of Science in Nursing and Associate Degree of Nursing programs in one southeastern state admit, identify, and graduate nursing students with learning disabilities, and to identify accommodations provided by these programs to promote success among this student population. Of the 54 programs surveyed, 45 responded. Almost 50% indicated that their program had admitted nursing students with learning disabilities and one-third reported graduating students with learning disabilities. Enrolled students with undiagnosed learning disabilities were identified during their course of studies by both faculty members and by students themselves. The most frequently reported accommodations for students were counselors, tutors, tape-recorded lectures, and computer access. As the number of students with learning disabilities seeking post-secondary education increases, nursing programs and nurse educators will be involved with greater numbers of students needing educational accommodations.
OBJECTIVE: To assess the effects of steady-state spontaneous hypothermia on multimodality evoked potentials and on peripheral nerve conduction in human poikilothermia. DESIGN AND SETTING: Case series at a university hospital. PATIENTS: Four patients (four women, aged 28 to 37 years) with acquired poikilothermia. MAIN OUTCOME MEASURES: Short-latency somatosensory, brain-stem auditory, and visual evoked potentials as well as motor and sensory peripheral nerve conduction velocity during steady-state spontaneous hypothermia and normothermia. RESULTS: The marked latency prolongation of all evoked potentials and decreased peripheral nerve conduction velocity observed during steady-state spontaneous hypothermia (mean +/- SD core temperature, 33.5 +/- 0.3 degrees C) compared with normothermia (36.9 +/- 0.4 degrees C) agrees with previous findings during short-term induced hypothermia. CONCLUSIONS: The unequivocal effect of sustained mild spontaneous hypothermia on evoked potentials and peripheral nerve conduction velocity underlines the importance of meticulous attention to even small alterations in core temperature in interpreting neurophysiological investigations.
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To assess the influence of treatment on the development of the somesthetic pathway in infants with congenital hypothyroidism receiving early treatment, median nerve somatosensory evoked potentials were measured during the 1st y of life. Twenty-nine infants were studied with six to seven somatosensory evoked potential tests per infant. The cervical latency (N13) divided by arm length and the first (N19) and second (N32) cephalic latencies as well as N13-N32 latency were measured. At diagnosis, all components showed a small but significant delay, which was not related to thyroxine (T4) levels before treatment. During treatment, T4 ranged from 50 to 290 nmol/L. At 12 mo, the cervical latency divided by arm length had normalized, whereas N19 and N13-N32 were more abnormal than at diagnosis. For N19, these abnormalities were related to a slow initial rise of T4 (< or = 100 nmol/L after 1 wk of treatment) and the initial N19 values. Abnormal N13-N32 values were associated with high T4 values during treatment (> 200 nmol/L) and the type of congenital hypothyroidism (partial or total deficiency in T4 production). Induction of therapy with l-triiodothyronine rather than l-thyroxine and the occurrence of low T4 values (< 100 nmol/L) after the 4th wk of therapy had no such effect. Our data suggest that, for normal CNS development, euthyroidism should be reached as soon as possible by adequate induction therapy. Thereafter, T4 supplementation should be strictly dosed, keeping the serum T4 values within narrow limits around the mean normal for age, because overtreatment, like initial undertreatment, may lead to CNS abnormalities at the end of the first year.
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The nutritional status of 121 psychiatric patients over the age of 60 years was examined on admission in a general psychiatric hospital. Before admission all patients were living independently. They were admitted directly from their homes. We found that the older psychiatric patient is evidently at risk for malnutrition. A quarter of the males had, according to the Quetelet's index, a low weight. Half of the males and one third of the females had a thiamin-deficiency, whereas half of all patients showed a deficiency of folic acid. Furthermore, in half of the males and one tenth of the females anaemia was diagnosed. Widowers and to a lesser extent also patients with an organic brain disease or psychotic disturbance ran a greater risk of malnutrition in comparison to their fellow patients. A relation between behaviour, measured by the Nosie (Nursing Observation Scale for Inpatient Evaluation) and the nutritional status was not found.
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At the present, the influence of intrauterine hypothyroidism on the fetus is estimated by bone age (BA). BA is also used as a predictor of later neuropsychologic development. The aim of this study was to investigate whether the neurophysiologic maturation of neonates with congenital hypothyroidism (CHT) is delayed at the start of therapy and, if so, whether this delay is comparable to that in BA. Twenty-seven infants with CHT were examined with median nerve somatosensory evoked potentials (SEP) before or within 1 wk after initiation of therapy. The effect of neonatal jaundice, a potential confounder of neonatal SEP, was also evaluated. Cervical (N13), first cephalic (N19), and second cephalic (N32) peak latencies were measured, as well as N13-N19 interval (central conduction time) and N13 latency divided by arm length. The SEP data of 103 normal infants were used as reference values. In the CHT newborns, a maturational delay was found for all SEP parameters. Preterm infants (n = 3) were conspicuously less affected than term patients. In term CHT infants, jaundice during the first postnatal week, but not late jaundice, had an additional adverse effect. SEP delay was not related to initial or actual T4 levels. BA delay exceeded SEP delay by several weeks. Our data suggest that the depressed T4 levels of the hypothyroid fetus and neonate affect the nervous tissue to a lesser degree than bone tissue and, further, that SEP is superior to BA as parameter for the evaluation of neurologic maturation of infants with CHT.
The effect of age on the maturation of median nerve somatosensory evoked potentials (SEPs) was studied in 103 normal neonates (24 preterm, 79 term) at the postconceptional age (PCA) of 36-48 weeks. The influence of birth weight was evaluated in 44 term neonates, aged 0-7 days, according to their gestational age (GA) stratified into three groups: A: 38-39 weeks (n = 15); B: 39.5-40.5 weeks (n = 15); C: 41-43 weeks (n = 14). The mean birth weight was not different in the three groups. For all infants the N13 latency recorded at cervical (CS2-Fz) level as well as the N19 onset and peak latency at cortical (C3'/C4'-Fz) level were measured. For these parameters and for the N13 latency divided by arm length (N13/AL) and the N19 ascending time (N19AT) the P50, P97 and P3 were calculated as a function of PCA. They were all decreasing in the 36-48 weeks period, fast before 40 weeks and slowly thereafter. The SEP values of groups, A, B and C were not different, but in each group the wave pattern of the cortical SEPs was more mature in the larger than in the smaller infants. For the groups A, B and C together birth weight (in SDS) correlated inversely with the N13/AL and the N19AT (both in SDS) (r = 0.73 and 0.52 respectively, p less than 0.001). Our data indicate that the progression of maturation of the various SEP components in the period of 36-48 PCA is non-linear.(ABSTRACT TRUNCATED AT 250 WORDS)
Somatosensory evoked potentials (SEPs) were studied in jaundiced and normal neonates on the day the highest bilirubin values were reached, 2-3 days later, and at five weeks. During the first week three groups were formed according to peak bilirubin values: A: greater than or equal to 250 mumol/l (n = 20), B: 125-250 mumol/l (n = 6), C: less than 125 mumol/l or no jaundice (n = 19). At five weeks 10 infants of group A were reinvestigated, together with 17 controls. Cervical (N13) and scalp SEPs (N19) were recorded with a variable number of stimuli. The SEPs of group B and C did not differ from each other. In group A the N13 peak latencies were within the range of group C at the first investigation, but prolonged at the second and third. The cortical components were prolonged at the first investigation, improved but still prolonged at the second, while the N19 peak latency was still prolonged at the third investigation. The central conduction time (CCT) correlated positively with the bilirubin level. Since a rapid decrease in the N19 amplitude was found for all groups from 25 to 100 stimuli, recordings should be done with a low number of stimuli (less than 100). Our findings indicate that both the periferal and the central components of the SEPs in the neonatal period are delayed by jaundice and that full recovery is not obtained at five weeks. The non-invasive SEP technique can be used as a daily monitor of the effect of bilirubin on the CNS.
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Median nerve somatosensory evoked potentials (SEPs) were investigated in 35 normal newborns aged 0-5 days. During stimulation at a regular frequency of 0.5/s, potentials deriving from cervical (CS2-Fz) or scalp (C3'-Fz) level were recorded with five different bandpasses (1-100 to 100-5,000 Hz (-6 dB/oct], with a variable number of stimuli (25-350) and in different arousal states: awake or in irregular sleep (non-quiet), or in regular sleep (quiet). The 1-100 Hz filter introduced a slight distorsion of the N13 and N19 (1) and (2) potentials but a better signal-to-noise ratio compared with the other filter settings. A 20-5,000 Hz bandpass resulted in an inacceptable distorsion of the N19 (1) and (2) peak. For the 100-5,000 Hz bandpass an almost complete suppression of the cortical components was obtained. With a 1-100 Hz bandpass a N13 and a N19 potential could be recorded in all infants; in 75% of them a bilobed N19 peak was present. In the quiet state (n = 13) either a bilobed N19 peak was observed with prolonged N19 (1) and (2) peak latencies compared with the non-quiet state or a large unilobed N19 wave. An increase in the number of stimuli from 25 to 100 resulted in a decrease of 33% in the amplitude of the N19(1) peak. We advocate to record SEPs in the neonatal period with a filter bandpass of 1-100 Hz and with a low number of stimuli (25-50), with attention for the arousal state of the infant.
We report our findings on a case of ependymoma in a one-year-old boy. A partial paresis of the left arm was found but the EEG and BAEP were normal. The EMG showed fibrillations and positive sharp waves in the paretic muscles and the SSEP showed a far field negativity. After removal of the cerebral process all neurophysiologic findings normalized. We discuss a hypothesis for the established clinical neurophysiological findings.
This study validates current hypotheses for the generation of so-called far-field or stationary somatosensory evoked potential (SEP) components. Changes in the volume conductor configuration and changes in the direction of nerve propagation are demonstrated to be capable of generating such components. Results are based on basic aspects of the theory of volume conduction. It is shown that in an essentially restricted volume conductor any disturbance of uniform nerve propagation in a homogeneous extracellular medium will lead to the generation of non-moving field components. A number of illustrative examples are presented in which intermingling of non-moving and propagating potential fields can be observed. These results can be helpful in unravelling complicated wave forms from the nervous system in which both types of potential field can be distinguished. It is shown that realistic changes within the volume conductor can lead to substantial far-field components. This type of volume conductor induced 'virtual generators' or 'secondary sources' is present in the peripheral nervous system and most probably also in the inhomogeneous structures of the brain.
Middle latency auditory evoked responses (MLRs) were recorded in 64 premature infants; serially in 54 of them. The last recording sessions occurred at 50-52 weeks conceptional age (CA), defined as the gestational age (GA) added to the chronological age. The MLRs were analyzed for the components PO, Na and Pa, and the interpeak latency difference (IPLD) Na-PO. The detectability rate of PO and Na reached 80-90% at about 30 weeks CA. Pa reached the highest rate of about 60% at 52 weeks CA. The degree of prematurity did not result in clear differences with respect to the parameter values. Also, the side of stimulation did not influence the MLR parameter values. The latency values of the MLR components are strongly age dependent. Topographic differences were found between the sides ipsi- and contralateral to stimulation. They are, however, different for PO, Na and Pa. The influence of the state of vigilance on the parameter values could generally only be established at CA levels of about 32 and 52 weeks CA. The amplitude values at 52 weeks CA are especially sensitive for sleep or awake state. The particular pattern of age dependency of the different components and their topographic differences are consistent with a differential generation of bilateral nature. The early appearance of the response supports the generation of an early functioning subcortical structure in the auditory pathway.
Composite group averages were constructed from cortical auditory evoked responses (ACRs), which are recorded sequentially at maximally 8 conceptional age levels in 5 groups of 49 preterm infants, with additional inclusion of the records of 16 prematures obtained at different conceptional age levels. The group averages for the 5 gestational age groups showed replicable waveforms at all conceptional age (CA) levels reflecting the intragroup stability of the ACR complex. From the earliest age levels, from 25 weeks CA on, ACR group averages can be obtained, containing relative low voltage fast waves and high voltage slow waves. The most outstanding developmental changes in the ACR complex are the waveform changes. Until about 36 weeks CA a premature waveform is found, followed by a transitional phase with low voltage noisy records. Finally the adult waveform is found in the measurements at three months after term date. The latency values of the group averages are determined by the waveform changes. Persistent amplitude differences are found for the slow late waves between the vertex and the central temporal derivations.
Auditory cortical evoked responses (ACRs) were recorded in 65 preterm infants, at least on 3 occasions in 48 of them. The infants were divided into 5 groups according to their gestational age (GA). The recording sessions were performed at 8 conceptional age (CA) levels, defined as the gestational age added to the chronological age. The last recordings were obtained at 50-52 weeks CA. The ACRs were analyzed for the primary complex containing middle latency components (MLR) and the secondary complex, containing the slow late components. The ACR records first appear at about 25 weeks CA, initiating the premature stage followed by a transitional stage around term date and the gradual development into the mature stage, achieved at 50-52 weeks CA. The detectability rate of the various components generally increased with increasing conceptional age, for some of the components, especially N2p and N2, this rate achieved a value of about 80%. The degree of prematurity did not influence appreciably the development of the ACR. The waveforms, and to a lesser extent the latency and amplitude values, are strongly age dependent. Remarkable topographic differences between the ACR parameter latency and more importantly amplitude values are found between the derivations from the vertex and the central temporal areas, supporting the theory of different generation sites for the ACR components. The premature and mature ACR appeared relatively insensitive to changes in the states of vigilance. The ACR in premature infants are useful in developmental studies with respect to the central audition in premature infants and might contribute in the clinical assessment on the quality of the premature central auditory system.