The effect of cyclophosphamide on T lymphocytes and T lymphocyte subsets in patients with chronic progressive multiple sclerosis

ABSTRACT— The lymphocytes in peripheral blood and cerebrospinal fluid of patients with chronic progressive multiple sclerosis (MS) were characterized with monoclonal antibodies to surface antigens of T cells, helper/inducer T cells and suppressor/cytotoxic T cells. The influence of cyclophosphamide treatment on these immune parameters was investigated.
Compared to healthy persons, the mononuclear cell fraction of the peripheral blood of patients with chronic progressive MS consisted of normal %s of T cells and helper/inducer T cells, but decreased %s of suppressor/cytotoxic T lymphocytes. Intensive as well as chronic treatment of MS patients with cyclophosphamide resulted in a decline in the %s of T cells and helper/inducer T cells, whereas the %s of suppressor/cytotoxic T cells returned to normal. In cerebrospinal fluid, cyclophosphamide also induced a relative decrease in the % of helper/inducer T cells and an increase in the % of suppressor/cytotoxic T cells compared to untreated MS patients. Intensive as well as chronic therapy with cyclophosphamide both led to a significant decrease in the absolute number of T cells and T cell subsets in the blood of the patients.     

Cross-modal multitasking processing deficits prior to the central bottleneck revealed by event-related potentials

We investigated whether concurrent processing of a tone (T1) interferes with early sensory-perceptual processing of a visual target (T2) in variants of the psychological refractory period paradigm using the event-related potential (ERP) method and 70-channel electroencephalographic recordings. T1, which required a speeded response, was presented in all trials. In half of the trials, T1 was followed by a bilateral visual display, T2, which also required a speeded response. A single T1-T2 stimulus onset asynchrony was adjusted dynamically to maximize task overlap in a hard-Task1 condition while minimizing task overlap in an easy-Task1 condition. The ERP to T1 in trials with only T1 presented (uncontaminated by T2) enabled us to subtract T1-related activity from the dual-task T2-locked ERPs. An attenuation of the T2-locked occipital N1 was observed in the hard-Task1 condition, relative to the easy-Task1 condition, both when T2 required a discriminative response and a detection response. An attenuation of the visual P1 component was also observed when T2 required a discriminative response. The N2pc was also attenuated, and the sustained posterior contralateral negativity (SPCN) was delayed, by concurrent processing in the discrimination task. Implications for models of dual-task interference are discussed.     

Emotional modulation of the attentional blink: the neural structures involved in capturing and holding attention

Perceiving a first target stimulus (T1) in a rapid serial visual presentation stream results in a transient impairment in detecting a second target (T2). This “attentional blink” is modulated by the emotional relevance of T1 and T2. The present experiment examined the neural underpinnings of the emotional modulation of the attentional blink. Behaviorally, the attentional blink was reduced for emotional T2 while emotional T1 led to a prolonged attentional blink. Using functional magnetic resonance imaging, we observed amygdala activation associated with the reduced attentional blink for emotional T2 in the face of neutral T1. The prolonged attentional blink following emotional T1 was correlated with enhanced activity in a cortical network including the anterior cingulate cortex, the insula and the orbitofrontal cortex. These results suggest that brain areas previously implicated in rather reflexive emotional reactions are responsible for the reduced attentional blink for emotional T2 whereas neural structures previously related to higher level processing of emotional information mediate the prolonged attentional blink following emotional T1.     

Influence of thyroid hormone treatment on the respiratory activity of cerebral mitochondria from hypothyroid rats. A critical re-assessment

Effects of treatment with thyroid hormones L-3,5,3'-tri-iodothyronine (T3) and L-thyroxine (T4) on oxidative energy metabolism in cerebral mitochondria from hypothyroid adult rats were examined. It was observed that T3 and T4 stimulated respiratory activity in a substrate-specific and dose-dependent manner. The results also suggest that the synthesis of cytochrome aa3 and of cytochrome c may be dependent on both T3 as well as T4 whereas higher concentrations than normal of T3 and T4 may have a catabolic influence on cytochrome b content.     

Sero-prevalence of Taenia solium cysticercosis and Taenia solium taeniasis in California, USA

OBJECTIVES: Taenia solium Cysticercosis is a leading cause of epilepsy and neurological disability in the developing world. It is caused by ingestion of the eggs of the tapeworm, T. solium Taeniasis. The prevalence of either T. solium Cysticercosis or T. solium Taeniasis in the United States in populations at risk is poorly understood. The primary objectives of this study are to perform the first study of the sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in an at-risk community in the USA, specifically rural Southern California; identify T. solium Taeniasis positive individuals, and treat positive individuals for the tapeworm T. solium Taeniasis. METHODS: Community based sero-prevalence study of antibodies to T. solium Cysticercosis and T. solium Taeniasis in 449 subjects living in a federally funded, predominantly Hispanic residential community; and in two migrant farm worker camps in rural Ventura County, California, USA. For this study, fingerstick blood samples were obtained. Serum immunoblots for both T. solium Cysticercosis and T. solium Taeniasis were performed. RESULTS: The sero-prevalence of T. solium Cysticercosis was 1.8% and the sero-prevalence of T. solium Taeniasis by serum immunoblot was 1.1%. Taenia solium Cysticercosis and T. solium Taeniasis antibodies were not detected in children. The sero-prevalence of T. solium Taeniasis was highest in the migrant farm worker community. Handwashing frequency was correlated with T. solium Taeniasis sero-positivity. CONCLUSION: The sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in this population, as detected by serum immunoblot, approximates the prevalence in some endemic areas of Latin America. Importantly, most patients likely had prior exposure, not active infection. This study establishes for the first time, the relative sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in at-risk populations in the United States.     

Selective reinnervation of intercostal muscles transplanted from different segmental levels to a common site

We transplanted external intercostal muscles from one of several thoracic (T) levels to the neck of adult rats. The cervical sympathetic trunk, which innervates the superior cervical ganglion, was cut, and its proximal end was apposed to the muscle. Preganglionic axons in the trunk reinnervated muscle fibers in the transplants. We determined the segmental origin of synaptic inputs to transplanted muscles by recording intracellularly from muscle fibers while stimulating individual ventral roots which supply axons to the trunk. In one series of experiments, T2 or T8 muscles were transplanted from the thorax to the neck of the same rat. While T2 and T8 muscles were reinnervated to a similar extent, they differed in the segmental origin of the innervation they received: T2 muscles received more inputs from rostral segments (T1 and T2) than did T8 muscles, and T8 muscles received more inputs from caudal segments (T4 to T6) than did T2 muscles. This difference between reinnervation of T2 and T8 muscles was detected both 2 to 4 weeks and 10 to 14 weeks after surgery. In a separate series, using rats of an inbred strain, T3, T4, or T5 muscles were transplanted from one rat to a separate host. Again, the average segmental origin of inputs to transplants from different levels differed systematically: it was most rostral to T3 muscles, intermediate to T4 muscles, and most caudal to T5 muscles. Finally, T3 and T5 muscles were soaked in a myotoxin, Marcaine, before reimplantation. This treatment kills muscle fibers but not myoblastic satellite cells; therefore, muscle fibers were replaced by regeneration. Marcaine-treated T3 and T5 muscles were successfully reinnervated but did not differ significantly in the segmental origin of their inputs. Our results show that adult mammalian muscles can be selectively reinnervated, and they raise the possibility that the selectivity is based on some positional quality that matches axons and muscles from corresponding segments. However, while differences among muscles survive denervation and transplantation, their expression or accessibility may change during regeneration.     

Physical and psychological status of 60-70-year-old citizens of Bern with neurotic symptoms in childhood--a study over more than 50 years (Emmental cohort)

The present study was undertaken to assess the influence of childhood variables (physical and emotional) to later well-being in a group of rural Swiss (Emmental Cohort). Our study is the first prospective cohort over a time period of more than 50 years. It includes 1537 children who were listed and assessed in 1942 (T1) because they had difficulties in school or were otherwise behaviorally disturbed. In 1995 (T2) more than 60% of the initial population could be reassessed by our study group. We found more subjects at T2 who had been rated as intelligent at T1. More subjects responding to T2 belonged to a higher social class, were more anxious, and had more psychosocial problems at T1. Social income at T2 is correlated to the social class at T1. More subjects have died since who were rated at T1 as being less intelligent, less neurotical, and having higher psychosocial problems. Twice as many men died than women. The emotional situation at T2 is significantly correlated to psychological well-being at T1. The somatic complaints at T2 correlate significantly to neurotic symptoms in childhood (T1). The more intelligent the children were rated at T1, the less emotional and somatic complaints were voiced at T2 and the better the psychic well-being was rated (T2). In addition, the former social milieu (T1) significantly determined somatic and psychological complaints at T2. Our data discern a significant correlation between actual status and former childhood variables more than 50 years later in a rural Swiss cohort (Emmental Cohort).     

Characterization of experimental ischemic brain edema utilizing proton nuclear magnetic resonance imaging

Correlations between T1 and T2 relaxation times and water and electrolyte content in the normal and ischemic rat and gerbil brains were studied by means of both nuclear magnetic resonance (NMR) spectroscopic and imaging methods. In the spectroscopic experiment on excised rat brains, T1 was linearly dependent on tissue water content and T2 was prolonged in edematous tissue to a greater extent than expected by an increase in water content, showing that T2 possesses a greater sensitivity for edema identification and localization. Changes in Na+ and K+ content of the tissue mattered little in the prolongation of relaxation times. Serial NMR imaging of gerbil brains insulted with permanent hemispheric ischemia offered early lesion detection in T1- and especially T2-weighted images (detection as soon as 30 min after insult). The progressive nature of lesions was also imaged. Calculated T1 and T2 relaxation times in regions of interest correlated excellently with tissue water content (r = 0.892 and 0.744 for T1 and T2, respectively). As a result, detection of cerebral ischemia utilizing NMR imaging was strongly dependent on a change in tissue water content. The different nature of T1 and T2 relaxation times was also observed.     

Sympathectomy for hyperhidrosis: should we place the clamps at T2–T3 or T3–T4?

Endoscopic thoracic sympathectomy is routinely used to treat severe hyperhidrosis. It is usually performed at the T2–T3 level of the nerve, but may produce less severe compensatory hidrosis if performed at a lower level. This study evaluates the outcome of 1,274 patients who underwent endoscopic thoracic sympathectomy for plamar, plantar, axillary or facial hyperhidrosis/blushing. Half of the patients were clamped at the T2–T3 level and half were clamped at the T3–T4 level. Postsurgical symptoms and side effects were assessed by interview. All of patients with palmar hyperhidrosis were cured or improved. Patients with plantar and axillary hyperhidrosis were more likely to be improved at T3–T4 level clamping. Patients with facial hyperhidrosis were more likely to be cured at T2–T3 level, but did show improvement at the T3–T4 level. Overall satisfaction was higher in the T3–T4 group. Some degree of mild compensatory sweating occurred in all patients. However, severe compensatory sweating was more common in the T2–T3 group. Around 2% of patients requested a reversal of their surgery. Endoscopic thoracic sympathectomy is a safe and effective treatment for hyperhidrosis. Clamping at the T3–T4 level has a more successful outcome. In particular, it appears to reduce the incidence of severe compensatory hidrosis.     

T2-Weighted and T2 Relaxometry Images in Patients with Medial Temporal Lobe Epilepsy

PURPOSE: Quantification of increased T2-weighted MRI signal that is associated with hippocampal sclerosis (HS) can be performed through (1) mean of hippocampal signal in single-echo T2 MRI and (2) hippocampal T2 relaxometry. It is not clear whether these two techniques are equivalent. In this study, we compare the hippocampal signal, detected by single-echo T2 quantification and by T2 relaxometry, in patients with medial temporal lobe epilepsy (MTLE). METHODS: We studied magnetic resonance images from 50 MTLE patients and 15 healthy subjects. We compared the quantification of a T2 signal from single echo images to T2 relaxometry, both obtained from a manually traced region of interest (ROI) in coronal slices involving the whole hippocampus. Repeated measures ANOVA was used to evaluate the differences in the distribution of the Z-scores from single-echo T2 quantification and T2 relaxometry within subjects. RESULTS: We observed a significant difference between the measurements obtained from single-echo T2 quantification and T2 relaxometry (P < .001). Measurements from head, body, and tail of the hippocampus were different (P=.04), with a significant interaction between anatomic location and type of measurement used (P= .008). Post hoc paired comparisons revealed that T2 relaxometry yielded greater Z-scores for the body (P= .002) and tail (P < .0001). CONCLUSIONS: For each subject with MTLE, T2 relaxometry was able to detect a higher signal in the body and tail of the hippocampus compared to single-echo T2. This is a possible indicator that T2 relaxometry is more sensitive in detecting T2 abnormalities within the body and tail of the hippocampus in patients with MTLE.     

Efficacy of a short-term psychoeducational intervention for persistent non-organic insomnia in severely mentally ill patients. A pilot study.

Insomnia in psychiatric patients is frequently underestimated in clinical practice. Usually drugs are prescribed for the treatment of this disorder but non-pharmacological intervention can be successfully used. The present study aimed at evaluating the efficacy of a two-session psychoeducational intervention in improving persistent non-organic insomnia and reducing the administration of PRN therapy in severely mentally ill patients. A pre-post study was performed on 36 psychiatric patients admitted to a residential psychiatric unit. The Nocturnal Sleep Onset Scale (NSOS) and Daytime Sleepiness Scale (DSS), the sleep onset latency, the time awake after sleep onset and the numbers of awakenings were gathered 2 weeks before the intervention (T0), immediately prior the intervention (T1), 2 weeks after the last session of the intervention (T2) and a 3-month follow-up (T3). The total number of administrations of PRN therapy from T0 to T1 and from T1 to T2 were also examined. A significant reduction was shown on the NSOS, the sleep onset latency and in the time awake after sleep onset from T1 to T2 and from T1 to T3, while no significant difference was found between T0 and T1. A significant decrease on the mean number of administrations of PRN therapy was also found between 15 days before the intervention (T0-T1) and 15 days after intervention (T1-T2). The initial results of this study seems to suggest the possible efficacy of a short-term psychoeducational intervention on improving persistent non-organic insomnia in severely mentally ill patients. Further control studies are necessary to confirm these findings.     

Multiple sclerosis : Distribution of T cells, T cell subsets and Ia-positive macrophages in lesions of different ages

Using monoclonal antibodies in combination with the PAP technique, total (T11+) T cells, helper-inducer (T4+) T cells, suppressor-cytotoxic (T8+) T cells and Ia+ cells (macrophages and B cells) were localized in frozen sections of multiple sclerosis (MS) lesions with varied disease activity. In acute MS, T11+, T4+, T8+ cells and Ia+ macrophages were found in large numbers throughout the lesion but were virtually absent from normal white matter. In active chronic MS lesions, the numbers of T11+, T4+ and T8+ cells increased from the center towards the edge of the lesion. T11+ and T4+ cells penetrated deeply into the normal-appearing white matter adjacent to the lesion, while T8+ cells were more confined to the lesion edge. Ia+ macrophages displayed a reverse distribution pattern to that of T cells. They showed the highest density in the lesion center and their numbers decreased slightly towards the lesion edge. Small numbers of T11+, T4+, T8+ and Ia+ cells were always present in normal white matter. In silent chronic MS lesions, the numbers of both T cells and Ia+ cells were significantly lower than in active chronic MS. While T11+ and T4+ cells were found throughout the central nervous system (CNS), T8+ cells were virtually absent from the lesion center. Ia+ macrophages were also present in small numbers throughout the CNS and, sometimes, showed some accumulation at the lesion edge. Thus, T cells and T cell subsets have been demonstrated to be involved in lesion pathogenesis in MS in that lesion progression was associated with T4+ cells while ongoing demyelination depended upon the presence of Ia+ macrophages.     

The diagnostic accuracy of 1.5 T versus 3 T non-echo-planar diffusion-weighted imaging in the detection of residual or recurrent cholesteatoma in the middle ear and mastoid

Purpose and backgroundThis study retrospectively compares diagnostic performance of 1.5 T versus 3 T non-echo planar diffusion weighted imaging with or without additional T1 and T2 sequences in the detection of residual and/or recurrent cholesteatoma.MethodsPatients with clinically suspected recurrent cholesteatoma or postoperative routine survey MR who subsequently underwent surgical procedure were retrospectively included (135 patients, 164 operated ears) from a large database. Patients underwent 1.5 T (128 ears) or 3 T MRI (36 ears), with non-echo planar DWI, T1 and T2 acquisitions. Two radiologists independently reassessed the images. Definitive surgical diagnosis was used as gold standard. Sensitivity, specificity and diagnostic odds ratio were evaluated.ResultsAccording to surgical diagnosis a cholesteatoma was present in 124 of 164 ears, corresponding with a prevalence of 75%. Sensitivity and specificity were lower for 3 T compared to 1.5 T, irrespective of whether additional T1 and T2-weighted sequences were used or not. Diagnostic odds ratios were higher for 1.5 T (34 and 12 for reader 1 and 2, respectively) compared to 3 T (3 and 4 for reader 1 and 2, respectively). Adding T1 and T2 sequences lowers sensitivity but increases specificity.ConclusionNon-epi DWI for the detection of residual/recurrent cholesteatoma is preferably performed on 1.5 T scanners over 3 T. The use of additional sequences regarding detection of cholesteatoma is debatable as it lowers sensitivity but increases specificity. However, these sequences may also be of use in diagnosing complications and planning surgical procedures in some hospitals.     

Visualization of thalamic nuclei on high resolution, multi-averaged T1 and T2 maps acquired at 1.5 T

The ability to differentiate noninvasively between the primary nuclear divisions of the thalamus has immediate clinical applicability for surgical planning and guidance of functional stereotactic procedures. Comparison of prior qualitative magnetic resonance imaging (MRI) studies carried out at field strengths of 1.5 and 4 Tesla have revealed contrast within the thalamus that varies with field strength, suggesting possible differences in the inherent T1 and T2 relaxation times of the constituent nuclei. We investigate this hypothesis through acquisition of high-resolution, multi-averaged deep-brain T1 and T2 maps of a healthy volunteer. Fourteen nuclei were identified using their center-of-mass coordinates (in Talairach space) and average T1 and T2 values obtained from regions of interest placed within each. Results from this analysis revealed significant differences in T1 and T2 between the nuclei with a T1 range from 700 to 1,400 ms and a T2 range from 89 to 122 ms, allowing visual discrimination between the major nuclei groups. Furthermore, the high-resolution images showed distinct borders of T1 and T2 hypointensity surrounding each nucleus, revealing structure not reported previously. These results confirm our hypothesis and demonstrate the potential high-resolution quantitative imaging for nucleus visualization and surgical planning.     

White matter and lesion T1 relaxation times increase in parallel and correlate with disability in multiple sclerosis

Previous studies have established the clinical relevance of hypointense lesions (“black holes”) on T1-weighted MRI as a surrogate marker for pathological change [36]. In contrast to measuring the volume of “black holes”, the direct measurement of T1 values allows an objective assessment of the changes contributing to hypointensity both in the focal lesions and in the normal appearing white matter (NAWM). The aims of this study were first, to determine the relationship between T1 values in the NAWM and in discrete lesions, second, to test the relationship between white matter T1 changes and measures of disability and third, to determine whether pathology leading to T1 change occurred in thalamic grey matter of patients with multiple sclerosis. 24 patients with clinically definite multiple sclerosis (13 with relapsing-remitting multiple sclerosis and 11 with secondary progressive multiple sclerosis) and 11 controls participated. White matter T1 histograms and mean T1 values for the thalamus were generated from whole brain T1 relaxation time maps measured using a novel echo-planar imaging based MRI sequence at 3Tesla. Tissue segmentation based on T2- and T1-weighted images allowed independent study of changes in lesions and NAWM. White matter T1 histograms from the patient group showed a reduced peak height and a shift towards higher T1 values (p = 0.028) relative to controls. The mean thalamic T1 was greater for secondary progressive patients than for healthy controls (p = 0.03). Mean white matter T1 values correlated significantly with disability (r = 0.48, p = 0.02). The mean T1 value in the T1-hypointense lesions correlated strongly with the mean T1 value in the NAWM (r = 0.80, p < 0.001). No significant relationship was found between mean white matter T1 value and cerebral volume (r = −0.23, p = 0.31). The T1 measurements extend previous observations suggesting that changes in the NAWM occur in parallel with pathology in lesions of MS. T1 measurements of either the total or NAWM therefore may provide a potentially observer- and scanner- independent marker of pathology relevant to disability in MS. Received: 1 October 2001, Received in revised form: 7 January 2002, Accepted: 15 January 2002     

Association of the C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase gene in patients with essential tremor in Turkey.

Essential tremor (ET) is a most common human movement disorder of unknown etiology. Previous reports have shown that the C677T polymorphism of methylenetetrahydrofolate reductase gene has been associated with neurodegenerative disorders. To investigate the role of methylenetetrahydrofolate reductase gene polymorphisms in essential tremor, we analyzed the alleles and genotypes of methylenetetrahydrofolate reductase (MTHFR) C677T and MTHFR A1298C in a total of 158 unrelated essential tremor patients and compared them with those of 246 unrelated healthy control subjects, using a polymerase chain reaction restriction fragment length polymorphism method. The allele frequency of MTHFR 677T was 35.76% in the essential tremor cases and 30.08% in the controls. We obtained statistically significant results for MTHFR677 and also for MTHFR1298. The MTHFR T677T genotype was overrepresented and was statistically significant. The T677T/A1298A and C677C/C1298C compound genotypes were similarly statistically significant. The C677C/A1298A compound genotype provided protection for essential tremor. In conclusion, the MTHFR 677T, 1298C alleles and MTHFR T677T genotype and T677T/A1298A, and C677C/C1298C compound genotypes are genetic risk factors for essential tremor in Turkey.     

右利手年轻人脑结构DTI的T_2-weighted trace图定量研究

目的定量研究右利手年轻人人脑结构扩散张量成像(DTI)的T2-weighted trace(T2-WT)参数值的特点,分析其与分数各向异性(FA)、平均扩散系数(MD)的关系。方法健康右利手年轻志愿者30例,男16名,女14名,平均年龄28.2岁,采集脑常规MRI及DTI图像,获取DTI的T2-WT、FA及MD三种后处理参数图:测量人脑13个部位的三种参数值,研究T2-WT参数图左右侧之间的差异,各部位参数值的性别差异,分析其与FA、MD的关系。结果 T2-WT值在桥脑、大脑脚、内囊前肢、半卵圆中心和豆状核双侧不对称,左侧>右侧,P=0.000～0.024,差异有统计学意义;各部位的T2-WT值男女差异无统计学意义,P=0.081～0.967;T2-WT与FA无相关关系,与MD之间有负相关关系,P=0.000。结论右利手年轻人脑结构T2-WT参数存在多个部位的左侧优势,T2-WT参数值男女差别无统计学意义,T2-WT与FA无相关关系,与MD之间有负相关关系。     

Comparative effects of morphine on leukocytic antigenic markers of monkeys and humans

Knowing the in vitro effects of morphine on monkey leukocytes would be helpful in extending the utility of a monkey model for psychoneuroimmunological investigations. Morphine effects on T11, Leu2a, and Leu3a antigenic markers on leukocytes from rhesus monkeys and humans were assessed by using single- and two-color cytofluorometric analyses. Kinetics of expression of these markers was determined after modulation of the original complement of T11 markers from the surface of T11(+) cells. Percentages of leukocytes detectable by directly staining these markers before modulation were within the expected range for monkey and human cells. Also, as expected, T11 modulation reduced the percentages of cells expressing T11. This reduction was particularly obvious for T11 in the single-color analyses, with reductions being greater for monkey than human cells. Furthermore, in the single-color analyses, the effects of morphine on kinetics of T11 expression were quite similar for both human and monkey cells. In the two-color analyses, the simultaneous expression of T11 and Leu3a markers was uniform for both monkey and human cells. The effects of morphine on kinetics of expression of these markers varied only slightly between species. On the other hand, the distribution of Leu2a on T11 cells was markedly different for monkey and human T-cells. Whereas all human Leu2a(+) cells expressed similar numbers of T11 receptors, monkey cells with high-density Leu2a expressed fewer T11 markers than those with low-density Leu2a. The effects of morphine on kinetics of Leu2a and T11 expression were at obvious variance between species.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maturation of human central auditory system activity: the T-complex.

OBJECTIVE: The purpose of this study was to evaluate and describe the maturation of a set of auditory evoked potentials (AEPs) described as the T-complex from a large group of children, adolescents, and young adults who ranged in age from 5 to 20 years of age. METHODS: The AEPs evoked by brief trains of clicks presented to the left ear were measured at 30 scalp-electrode locations. Analyses focused on age-related latency and amplitude changes in the T-complex recorded at the temporal electrode sites T3 and T5 over the left hemisphere and T4 and T6 over the right hemisphere. The maturation of the T-complex components Na, Ta, and Tb was contrasted with those of the obligatory AEPs P1, N1b, and P2 measured at electrodes C3 and C4. RESULTS: T-complex activity was present in the grand average AEPs of all 14 age groups spanning ages 5-20 years. T-complex components recorded at electrodes T3 and T4 differed in both morphology and maturation rate from those recorded at T5 and T6. In contrast to the prolonged maturation of AEP latency measured at electrodes T5 and T6, the T-complex components measured at electrodes T3 and T4 did not show a significant overall change in peak latency as a function of age. Consistent amplitude and latency correlations were found between the obligatory AEP components P1, N1b and P2 recorded at C3 and C4 and the T-complex components measured at T5 and T6, but not T3 and T4. CONCLUSIONS: Distinct patterns of AEP maturation were measured at electrode sites commonly used to record the T-complex. At scalp electrodes located over more posterior temporal areas (T5 and T6), the AEPs were characterized by a prolonged pattern of maturation very similar to that measured at the central electrodes C3 and C4. These findings and others reported in this paper provide strong evidence that the AEPs recorded at electrodes T5 and T6 are not T-complex peaks. In contrast, the AEPs measured at electrodes T3 and T4 over more anterior temporal scalp areas appear largely independent of activity measured at the central electrode locations. The T-complex peaks Ta and Tb measured at these scalp locations mature early, with no overall significant age-related changes in peak latencies. SIGNIFICANCE: The T-complex is recorded from the temporal electrodes T3 and T4 represents activity of secondary auditory cortex better than, and independent from, midline potentials. Its robust presence in 5-8 year olds supports its potential usefulness in assessing language impairment.     

T2-SPACE imaging of the cauda equina for the assessment of leptomeningeal metastatic disease

The diagnosis of leptomeningeal metastatic disease (LMD) is frequently challenging and MRI of the spine is an important part of the diagnostic paradigm. We sought to examine the value of adding 3-dimensional, heavily T2-weighted, Sampling Perfection with Application optimised Contrasts using different flip angle Evolution (T2-SPACE) imaging of the lumbar spine to the MRI protocol for patients with suspected LMD. MRI spine examinations including T2-SPACE imaging of the lumbar spine performed for suspected or known LMD were retrospectively reviewed by a neuroradiologist to determine the additional benefit of the T2-SPACE sequence. The accuracy of T2-SPACE was also compared to contrast-enhanced T1-weighted imaging (ceT1WI) and standard T2-weighted imaging (T2WI). 59 patients with T2-SPACE were identified over a 20-month period, 17 having abnormal appearances on ceT1WI, including 12 with appearances consistent with LMD. In eight of these 12 patients, nodules visible on T2-SPACE were visible on T2WI, though T2-SPACE improved the temporal comparison of slowly progressive cauda equina nodules in two cases. In three patients, T2-SPACE identified nodules which were not readily identifiable on T2WI, though were visible on ceT1WI. In one patient, LMD visible on ceT1WI was not appreciable on T2-SPACE or T2WI due to the lack of a nodular component. In six patients, T2WI showed equivocal nodularity, which could be confidently attributed to facet joint arthropathy or a tortuous vessel. In conclusion, T2-SPACE has high sensitivity and specificity for the detection of nodular lesions of the cauda equina and can confidently characterise equivocal findings on standard T2WI.