Outcomes of ATA Low-Risk Pediatric Thyroid Cancer Patients Not Treated With Radioactive Iodine Therapy

CONTEXT

The American Thyroid Association (ATA) Pediatric Guidelines recommend patients not receive radioactive iodine therapy (RAIT) for differentiated thyroid cancer (DTC) confined to the thyroid. Since publication, there is ongoing concern whether withholding RAIT will result in a lower rate of remission.

OBJECTIVE

This study explores whether ATA low-risk patients treated with and without RAIT achieved similar remission rates.

METHODS

Medical records of patients <19 years old diagnosed with DTC and treated with total thyroidectomy between 2010 and 2020 were reviewed. Multivariate logistic regression was performed to evaluate factors influencing RAIT administration and remission rate.

RESULTS

Ninety-five patients with ATA low-risk DTC were analyzed: 53% (50/95) and 47% (45/95) were treated with and without RAIT, respectively. RAIT was used to treat 82% of patients before 2015 compared with 33% of patients after 2015 (P < .01). No significant difference in 1-year remission rate was found between patients treated with and without RAIT, 70% (35/50) vs 69% (31/45), respectively. With longer surveillance, remission rates increased to 82% and 76% for patients treated with and without RAIT, respectively. Median follow-up was 5.8 years (IQR 4.3-7.9, range 0.9-10.9) and 3.6 years (IQR 2.7-6.6; range 0.9-9.3) for both cohorts. No risk factors for persistent or indeterminate disease status were found, including RAIT administration, N1a disease, and surgery after 2015.

CONCLUSION

Withholding RAIT for pediatric patients with ATA low-risk DTC avoids exposure to radiation and does not have a negative impact on remission rates. Dynamic risk stratification at 1-year after initial treatment is a suitable time point to assess the impact of withholding RAIT for these patients.

Pulmonary injury after radioactive iodine therapy in pediatric papillary thyroid cancer: a case report

INTRODUCTION

Radiation-induced lung injury is a rare complication of radioactive iodine therapy (RAIT) in pediatric thyroid cancer treatment. In this case report, we describe a pediatric patient with an ERC1::RET-positive classic papillary thyroid carcinoma who developed progressive respiratory symptoms and chest imaging abnormalities following RAIT for lymph node and pulmonary disease.

CASE PRESENTATION

A pediatric patient with ERC1::RET-positive classic papillary thyroid carcinoma was hospitalized for pulmonary decompensation three months following one empiric dose of RAIT. Testing revealed no evidence of infection or progression of pulmonary metastases, and there was no improvement with empiric antibiotic therapy for pneumonia. Despite empiric anti-inflammatory therapies, the patient remains symptomatic from a respiratory standpoint with requirement for supplemental oxygen and evidence of fibrotic changes on chest imaging.

CONCLUSIONS

This patient's pulmonary condition is consistent with radiation-induced pulmonary injury including development of pulmonary fibrosis. With the availability of RET fusion targeted inhibitors, this case highlights a rare pulmonary side effect of radioactive iodine for clinicians to recognize. Upfront targeted therapy protocols may help avoid radioactive iodine-associated adverse reactions.

Thyroid Ultrasound Screening in Childhood Cancer Survivors following Radiotherapy

INTRODUCTION

Childhood cancer survivors (CCS) are at risk for radiotherapy (RT) late effects, including second malignancies. Optimal screening for differentiated thyroid cancer (DTC) in CCS post-RT remains controversial. We assessed the outcome of thyroid ultrasound (US) surveillance in CCS exposed to RT.

METHODS

306 CCS were surveilled with thyroid US between 2002-2021. Surveillance was dependent on age at the time of primary diagnosis, interval from receipt of RT, and individual provider. Thyroid US, clinicopathologic features, and outcomes were described. Cutpoints of CCS RT age associated with varying risk of nodule presentation were explored. The selected cutpoints were used to define age categories, which were then used to compare thyroid nodule-related outcomes. Risk factors for thyroid nodule(s) were evaluated using multivariate logistic regression (odds ratio [OR] [95% confidence interval]).

RESULTS

The most common CCS diagnoses were leukemia (32%), CNS tumor (26%), and neuroblastoma (18%). Patients received TBI (45%) and/or RT to craniospinal (44%), chest (11%), and neck regions (6%). About 49% (n = 150) of patients had thyroid nodule(s). Forty-four patients underwent surgery, and 28 had DTC: 19 with American Thyroid Association (ATA) low-risk classification, 2 with ATA intermediate-risk, and 7 with ATA high-risk disease. Age cutpoint analyses identified cutpoints 3 and 10; hence, ≤3, >3 to ≤10, and >10 years were used. Of the 9 patients with intermediate- or high-risk disease, 8 were ≤10 years and 1 was >10 years at the time of RT. Female sex (OR = 1.62 [1.13-2.12] p = 0.054) and greater interval between RT and first US (OR = 1.10 [1.04-1.16] p = 0.001) were independent risk factors for nodule presentation.

CONCLUSIONS

Thyroid US surveillance may be beneficial for CCS exposed to RT at younger ages (≤10 years) for earlier detection of DTC, prior to developing advanced metastatic disease.

Impact of Definitive Surgery for Graves' Disease on Adolescent Disease-Specific Quality of Life and Psychosocial Functioning

Introduction: Pediatric Graves' disease (GD) is associated with hyperthyroid symptoms that impact psychosocial and physical functioning. Total thyroidectomy (TT) is a definitive treatment option that replaces antithyroid medication. While studies have examined health-related quality of life (QOL) in adults, there are no data describing impacts of TT in pediatrics. In this prospective longitudinal study, we explored the impact of TT on disease-specific QOL and satisfaction with TT and scar appearance in adolescent patients with GD undergoing TT. Methods: Patients 12-19 years old pursuing TT for GD and their parents were recruited to complete surveys before and at least 6 months after TT. Surveys assessed motivations for pursuing TT, QOL, perceived stigmatization, self-esteem, scar appearance, and surgery satisfaction. Paired scores were compared using Wilcoxon signed-rank tests, and subscore associations were assessed using Spearman association tests. Results: Thirty-seven patient-parent dyads completed baseline surveys, including 20 patient-parent dyads completing pre- and post-TT surveys. At baseline, patients reported physical and cognitive symptomology, including tiredness, anxiety, and emotional susceptibility through ThyPRO. Psychosocial functioning at school was low through PedsQL. Disease-specific QOL significantly improved after TT, with notable improvements associated with resolution of goiter (median change = -26.14, p = 0.003), hyperthyroid symptoms (median change = -43.75, p = 0.002), tiredness (median change = -26.79, p = 0.017), cognitive impairment (median change = -14.58, p = 0.035), anxiety (median change = -33.33, p = 0.010), and emotional susceptibility (median change = -28.99, p = 0.035). Physical (median change = 18.75, p = 0.005) and school-related functioning (median change = 30.00, p = 0.002) also significantly improved post-TT. Reported GD-associated eye symptomology (thyroid eye disease) was the second lowest scoring ThyPRO subscore at baseline and improved after surgery (median change = 14.06, p = 0.03). Families reported median recovery by two months, high satisfaction with the outcomes of TT, and minimal concerns over scar appearance. No permanent surgical complications (i.e., recurrent laryngeal nerve damage or hypoparathyroidism) were sustained. Conclusions: In the setting of a high-volume surgeon with low complication rates, TT for GD in pediatric populations may have substantial beneficial effects on disease-specific QOL and psychosocial functioning, with minimal adverse complaints about scar appearance.

Indeterminate Thyroid Fine-Needle Aspirations in Pediatrics: Exploring Clinicopathologic Features and Utility of Molecular Profiling

INTRODUCTION

The diagnostic utility of molecular profiling for the evaluation of indeterminate pediatric thyroid nodules is unclear. We aimed to assess pediatric cases with indeterminate thyroid fine-needle aspiration (FNA) alongside clinicopathologic features and mutational analysis.

METHODS

A retrospective review of 126 patients with indeterminate cytology who underwent FNA between January 2010 and December 2021 at the Children's Hospital of Philadelphia was performed. Indeterminate cases defined by The Bethesda System for Reporting Thyroid Cytopathology (AUS/FLUS or TBSRTC III; FN/SFN or TBSRTC IV; SM or TBSRTC V) were correlated to clinicopathologic and genetic characteristics.

RESULTS

Of the 114 surgical cases, 48% were malignant, with the majority of malignant cases diagnosed as follicular variant of papillary thyroid carcinoma (28/55). Risk of malignancy increased with TBSRTC category: 23% for AUS/FLUS, 51% for FN/SFN, and 100% for SM nodules. There were significant differences in surgical approach (p < 0.01), performance of lymph node dissection (p < 0.01), histological diagnosis (p < 0.01), primary tumor focality/laterality (p = 0.04), and lymphatic invasion (p = 0.02) based on TBSRTC classification, with resultant differences in post-surgical risk stratification per American Thyroid Association (ATA) Pediatric Guidelines (p = 0.01). Approximately 89% (49/55) of cases were classified as ATA low risk, and 5 of 6 patients with ATA intermediate- or high-risk disease had SM cytology. Somatic molecular testing was performed in 40% (51/126) of tumors; 77% (27/35) of malignant cases and 38% (6/16) of benign cases harbored driver alteration(s). Of the driver-positive malignant cases, 52% (14/27) were associated with low risk (DICER1, PTEN, RAS, and TSHR mutations), 33% (9/27) were associated with high risk (BRAF mutations and ALK, NTRK, and RET fusions), and 15% (4/27) had unreported risk for invasive disease (APC, BLM, and PPM1D mutations and TG-FGFR1 fusion). Incidence of high-risk drivers increased with TBSRTC category. Approximately 23% (8/35) of patients harboring thyroid malignancy did not have an identifiable driver alteration.

CONCLUSIONS

Molecular analysis is useful to discriminate benign and malignant thyroid nodules with indeterminate cytology. Patients with driver genetic alteration(s) and indeterminate cytology should consider surgical management secondary to the high incidence (82%; 27/33) of thyroid malignancy in these patients.

Clinicopathologic Characteristics of Pediatric Follicular Variant of Papillary Thyroid Carcinoma Subtypes: A Retrospective Cohort Study

Introduction: Follicular patterned thyroid nodules with nuclear features of papillary thyroid carcinoma (PTC) encompass a range of diagnostic categories with varying risks of metastatic behavior. Subtypes include the invasive encapsulated follicular variant of PTC (Ienc-fvPTC) and infiltrative fvPTC (inf-fvPTC), with tumors lacking invasive features classified as noninvasive follicular thyroid neoplasms with papillary-like features (NIFTPs). This study aimed to report the clinical and histological features of pediatric cases meeting criteria for these histological subtypes, with specific focus on Ienc-fvPTC and inf-fvPTC. Methods: In this retrospective cohort study, pediatric patients with thyroid neoplasms showing follicular patterned growth and nuclear features of PTC noted on surgical pathology between January 2010 and January 2021 were retrospectively reviewed and classified according to the recent 2022 World Health Organization (WHO) criteria. Clinical and histopathologic parameters were described for NIFTP, Ienc-fvPTC, and inf-fvPTC subtypes, with specific comparison of Ienc-fvPTC and inf-fvPTC cases. Results: The case cohort included 42 pediatric patients, with 6 (14%), 25 (60%), and 11 (26%) patients meeting criteria for NIFTP, Ienc-fvPTC, and inf-fvPTC, respectively. All cases were rereviewed, and 5 patients originally diagnosed with Ienc-fvPTC before 2017 were reappraised as having NIFTPs. The NIFTP cases were encapsulated tumors without invasive features, lymph node or distant metastasis, or disease recurrence. Ienc-fvPTC tumors demonstrated clearly demarcated tumor capsules and capsular/vascular invasion, while inf-fvPTC tumors displayed infiltrative growth lacking a capsule. inf-fvPTC cases had increased prevalence of malignant preoperative cytology, lymph node metastasis, and distant metastasis (p < 0.01). These cases were treated with total thyroidectomy, lymph node dissection, and subsequent radioactive iodine therapy. Preliminary genetic findings suggest a predominance of fusions in inf-fvPTC cases versus point mutations in Ienc-fvPTC (p = 0.02). Conclusions: Pediatric NIFTP and fvPTC subtypes appear to demonstrate alignment between clinical and histological risk stratification, with indolent behavior in Ienc-fvPTC and invasive features in inf-fvPTC tumors.

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

Thyroid gland definitive ultrasound screening in childhood cancer survivors following radiotherapy

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Background: Childhood cancer survivors (CCS) are at risk for radiotherapy (RT) late effects, including second malignancies. Optimal screening for thyroid cancer (TC) in CCS post-RT remains controversial. We assessed the clinical benefit of thyroid ultrasound (US) surveillance in CCS exposed to RT. Methods: 316 CCS (175 males) were prospectively surveilled with thyroid US between 2002 and 2021 at the Children’s Hospital of Philadelphia. Patients were screened upon referral to the Survivorship Program. Thyroid US, clinicopathologic features, and endocrine-related outcomes were ascertained. Outcomes were compared using primary CCS diagnosis age cohorts of ≤ 3, > 3 to ≤ 10, and > 10 years. Risk factors for thyroid nodule(s) and TC were evaluated using Kruskal Wallis and ANOVA [OR (95% CI)]. Results: The most common CCS diagnoses were leukemia (32%), CNS tumor (26%), and neuroblastoma (18%). Patients received TBI (43%) and/or RT to craniospinal (43%), chest (13%), and neck regions (7%). About 48% (n = 152) of patients presented thyroid nodule(s) (Table). Forty-six patients underwent surgery, and 28 had TC, including 19 with ATA low-risk, 2 with ATA intermediate-risk, and 7 with ATA high-risk disease. Of the 9 patients with intermediate- or high-risk disease, 5 were ≤ 3 years, 3 were > 3 to ≤ 10 years, and 1 was > 10 years at the time of RT exposure. Eight patients with TC demonstrated pathogenic variant(s). RT exposure at ≤ 3 years old conferred 2-fold increased risk for nodule(s) compared to RT at > 10 years [OR = 2.14 (1.44-2.84) p = 0.03]. Female sex [OR = 1.73 (1.25-2.21) p = 0.02] and greater interval between RT and first US [OR = 1.10 (1.04-1.15) p = 0.001] were additional independent risk factors. Conclusions: Younger age at RT exposure is associated with increased risk of and shorter latency for developing TC. Thyroid US surveillance appears most beneficial in CCS exposed to RT ≤ 3 years old in an effort to diagnose TC at an earlier stage prior to metastasis. [Table: see text]

Utility of Fine-Needle Aspirations to Diagnose Pediatric Thyroid Nodules

INTRODUCTION

Risk of malignancy for pediatric thyroid nodules classified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is not well defined. Correlations between risk of malignancy and ancillary clinical data remain inconclusive. We report a single institutional experience of fine-needle aspiration (FNA) to improve upon current management paradigm of thyroid nodules.

METHODS

A retrospective chart review of 575 thyroid nodules was performed of 324 patients who underwent 340 FNAs between 2008 and 2018 at the Children's Hospital of Philadelphia. Demographics, ultrasound (US) characteristics, FNA cytology, surgical pathology, and ancillary data were reviewed.

RESULTS

The rate of malignancy according to TBSRTC was 0.0% for category I, 0.8% for category II, 15.6% for category III, 54.5% for category IV, 100.0% for category V, and 100.0% for category VI. The cumulative Thyroid Imaging Reporting and Data System (TI-RADS) score was significantly correlated with benign and malignant nodules on pathology (p < 2.2e-16). Distribution of TI-RADS for cytologically indeterminate nodules with benign or malignant pathology revealed significant differences for composition (p = 3.20e-8) and echogenic foci (p = 0.005) but not for echogenicity (p = 0.445), shape (p = 0.160), margins (p = 0.220), and size (p = 0.105). Distributions of thyroid-stimulating hormone levels between benign and malignant patients was significant (p = 1.58e-3).

CONCLUSIONS

Nodules with TI-RADS scores >3 should undergo FNA, irrespective of size; surgical resection is recommended for nodules classified as TBSRTC category IV and V due to high risk of malignancy. US surveillance instead of FNA can be performed for nodules with TI-RADS scores ≤3.

Clinical Course of Early Postoperative Hypothyroidism Following Thyroid Lobectomy in Pediatrics

Introduction: Thyroid lobectomy reduces risks of surgical complications and need for levothyroxine (LT4). We aimed at identifying the clinical course and risk factors for postlobectomy hypothyroidism to optimize surgical counseling and management in pediatric patients undergoing lobectomy. Methods: Clinical and biochemical presentations pre- and postlobectomy were retrospectively reviewed for 110 patients who underwent thyroid lobectomy between 2008 and 2020 at the Children's Hospital of Philadelphia. Results: Approximately 28.2% of patients (31/110) developed postlobectomy hypothyroidism defined by an elevated thyrotropin (TSH) level, including 24.5% (27/110) with subclinical hypothyroidism (TSH >4.5 and <10.0 mIU/L) and 3.6% (4/110) with overt hypothyroidism (TSH >10.0 mIU/L). LT4 was initiated in 12.7% (14/110) of cases. Most patients (81.6%; 84/103) recovered euthyroidism within 12 months postlobectomy. When excluding patients with autonomous nodule(s), median preoperative TSH was 1.09 (interquartile range [IQR] = 0.70-1.77) mIU/L and 1.80 (IQR = 1.02-2.68) mIU/L in euthyroid and hypothyroid patients, respectively, with multivariate logistic regression confirming the association between an increased preoperative TSH and postlobectomy hypothyroidism (odds ratio = 1.8 [confidence interval 1.08-3.13], p = 0.024). Of the patients who underwent thyroid lobectomy and developed postoperative hypothyroidism (n = 31), 38.7% (12/31) had a preoperative diagnosis of an autonomously functioning thyroid nodule. Conclusions: Thyroid function should be evaluated postlobectomy to assess the need for LT4. LT4 should be considered if the TSH remains elevated, especially if an upward trend is observed or TSH is >10.0 mIU/L. Suppressed preoperative TSH associated with autonomous nodules is an independent risk factor for postlobectomy hypothyroidism.

The Clinical Spectrum of PTEN Hamartoma Tumor Syndrome: Exploring the Value of Thyroid Surveillance

INTRODUCTION

Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) comprises a collection of clinical features characterized by constitutional variants in PTEN. Several guidelines recommend thyroid screening, beginning at the pediatric age at the time of PHTS diagnosis; however, the benefits of early surveillance has not been well defined.

METHODS

We conducted a retrospective investigation of patients followed up at the Children's Hospital of Philadelphia with a diagnosis of PHTS between January 2003 and June 2019. In total, 81 patients younger than 19 years were identified.

RESULTS

The most common clinical feature at presentation was macrocephaly (85.1%), followed by impaired development (42.0%), skin/oral lesions (30.9%), and autism spectrum disorder (27.2%). A total of 58 of 81 patients underwent thyroid surveillance, with 30 patients (51.7%) found to have a nodule(s). Ultimately, 16 patients underwent thyroidectomy, with 7.4% (6/81) diagnosed with thyroid cancer. All thyroid cancer patients were older than 10 years at diagnosis, and all displayed low-invasive behavior. Of the patients younger than 10 years at the time of thyroid ultrasound (US) surveillance, 71.4% (15/21) had a normal US. The remaining 6 patients had thyroid nodules, including 4 undergoing thyroid surgery with benign histology.

DISCUSSION/CONCLUSION

Patients with macrocephaly, impaired cognitive development and thyroid nodules, and/or early-onset gastrointestinal polyps should undergo constitutional testing for PHTS. There does not appear to be a clinical advantage to initiating thyroid US surveillance before 10 years of age. In PHTS patients with a normal physical examination, thyroid US surveillance can be delayed until 10 years of age.

Selected management approaches to central auditory processing disorders

This is a commentary on three key aspects of the management of central auditory processing disorders in children. It is an update on some selected approaches for the management of auditory processing problems. Auditory training techniques that are theoretically based and for which empirical data are emerging are addressed. The second part of our commentary deals with methods of enhancing acoustic speech signals. Discussions on clear speech, acoustic modifications of the listening environment, and the utilization of assistive listening devices are presented. The final part of the article reviews linguistic and cognitive interventions for people with auditory processing problems. Topics in this section include approaches to facilitate phonological awareness, vocabulary building, prosodic feature recognition, and use of metacognitive abilities.

Distortion product otoacoustic emissions: hit and false-positive rates in normal-hearing and hearing-impaired subjects

OBJECTIVE

This study aimed to establish hit and false-positive rates for distortion product otoacoustic emissions (DPOAEs) using a commercial instrument.

STUDY DESIGN

This was a prospective study. The examiners performing the DPOAEs were blinded to pure-tone audiometric results. A decision matrix analysis was used to determine hit and false-positive rates for absolute amplitude, three amplitude-to-noise ratios, and three conditions that combined these two parameters.

SETTING

The study was performed at a tertiary care, outpatient clinical laboratory facility.

PATIENTS

Subjects with normal hearing and those with sensorineural hearing loss participated in the study.

MAIN OUTCOME MEASURES

Main outcome measures were hit and false-positive rates for various DPOAE measures.

RESULTS

Hit and false-positive rates were better for high than low frequencies. As absolute amplitude and amplitude-to-noise ratios increased hit and false-positive rates improved. Optimal hit rates generally exceeded 80%; false-positive rates were approximately 20% in the high-frequency range. Although the absolute amplitude measures seemed more useful than various ratio measures, there were advantages to using both parameters clinically.

CONCLUSIONS

DPOAEs have acceptable hit and false-positive rates for high frequencies but not for lower frequencies. DPOAE amplitude-to-noise ratios of +3 and even +6 dB may not be clinically feasible based on the current data. The overall findings obtained on the commercial instrument in this study compare favorably with previous studies of a similar nature.

Comparison of standard and abbreviated distortion product otoacoustic emissions procedures

Standard and abbreviated distortion product otoacoustic emissions (DPOAEs) procedures derived using the Grason Stadler Model 60 instrument were compared. The standard and abbreviated procedures were compared at frequencies of 1000, 1250, 1593, 2000, 2531, and 3187 Hz for 48 ears from 28 subjects. The subject pool included individuals with normal hearing and those with sensorineural hearing loss. The abbreviated procedure correlated well with the standard procedure for DPOAE amplitude cross all frequencies tested. The two procedures were also highly similar in categorizing the subjects in regard to normal or abnormal hearing sensitivity. It appears that the shorter analysis time for the abbreviated procedure had little effect on its accuracy. Although the abbreviated procedure has an obvious frequency limitation, it may have some clinical advantages for hearing screening.

Audiologic evaluation and management of adults with auditory processing disorders

Over the past decade there has been an increase in the number of adults with persistent hearing complaints coincident with normal audiometric findings who are seeking audiologic follow-up in an effort to determine the basis of their hearing difficulties. Although in some cases the etiology of the hearing difficulties is clearly not related to compromise of the auditory system, in many cases the basis of the difficulties can be linked to auditory system compromise. This article reviews the various etiological bases for these hearing difficulties and the symptoms most commonly reported by adults who fit into this category of patients. The application of peripheral and central auditory tests in the assessment of these patients is described and implications of test findings for management of the individual with these deficits are discussed.

"Negative" ABR findings in an individual with a large brainstem tumor: hit or miss?

This case illustrates the importance of determining the precise locus and extent of a lesion when attempting to correlate lesion site with auditory brainstem response (ABR) findings. The failure to document significant ABR findings in an individual with a large mass involving the low brain stem may initially appear to constitute a threat to the sensitivity of the ABR; however, careful review of the radiologic evidence in this case suggests that sensitivity did not suffer, but rather that the specificity of the procedure was upheld. Moreover, the value of electronystagmography (ENG) in the assessment of an individual with a lesion in the region of the low brain stem and severe vestibular symptoms is demonstrated.

P300 results in patients with lesions of the auditory areas of the cerebrum

Auditory P300 event-related potentials were obtained at C3 and C4 recording sites from 20 patients with cerebral lesions that affected auditory areas of the brain. The patient group was matched for age and hearing sensitivity to a control group of 20 subjects. There were significant differences between the two groups for both latency and amplitude of the P300. Eight patients demonstrated an absent P300 for at least one recording condition while all subjects in the control group had readable P300s in all recording conditions. A subset of patients with lesions limited to one hemisphere showed no laterality effects for amplitude or latency of the P300 for the ear or electrode that was either ipsilateral or contralateral to the lesion. In comparison to the P2 evoked potential, the P3 was more sensitive to neurologic lesions.

Canal electrode electrocochleography in patients with absent wave I ABRs

Fifteen patients (23 ears) who demonstrated no recordable wave I at the time of clinical auditory brainstem response testing were subsequently retested under three auditory brainstem response-electrocochleography conditions. One condition was the traditional auditory brainstem response, another was the auditory brainstem response with electrocochleography filtering, and the third was an electrocochleographic condition using a canal electrode (Tiptrode). The electrocochleographic recording condition provided more readable wave I responses than the other conditions. In addition, the electrocochleographic condition provided wave I amplitudes that were greater than those of the traditional auditory brainstem response. The later waves of the auditory brainstem response (III and V) were similar in wave presence amplitudes and latencies for all three test conditions.

Duration pattern recognition in normal subjects and patients with cerebral and cochlear lesions

Three groups of subjects were tested on a duration pattern recognition task. The groups included normal subjects, subjects with cochlear hearing loss, and subjects with lesions involving but not limited to the auditory areas of the cerebrum. Results indicated no significant difference in pattern recognition between the normal subjects and subjects with cochlear hearing loss. However, the subjects with cerebral lesions performed significantly more poorly than either the normal subjects or those with cochlear hearing loss. In comparing pattern recognition performance for the ears ipsilateral and contralateral to the lesioned hemispheres no differences were noted. Rather, when a central lesion was present, both ears generally yielded abnormal scores.

The dichotic rhyme task: results in split-brain patients

Monosyllabic rhyme words were dichotically presented to normal and complete split-brain subjects. In the normal adult population, only one of the words in the dichotic condition was identified. Hence, normal performance was about 50%, with a small but significant right-ear advantage. The split-brain patients yielded the expected marked left deficit, as seen on other dichotic speech tests, and demonstrated a right-ear enhancement, producing a large interear difference. This right-ear enhancement on the dichotic rhyme task (DRT) may suggest a release from central auditory competition in the left hemisphere. The dichotic rhyme task's normative data results and sensitivity to lack of callosal transmission make it worthy of further clinical and basic research.

Topographic mapping of brain electrical activity in the assessment of central auditory nervous system pathology

Topographic mapping of brain electrical activity is a method of converting electrical measurements of brain activity (evoked potential and EEG) into quantitative data that then can be displayed as colored visual maps. In this article, we review the basic principles underlying the procedures involved and then discuss their use in the assessment of central auditory nervous system (CANS) pathology. Finally, we highlight some of the limitations of the procedures as presently used.

Central auditory assessment: thirty years of challenge and change

In this paper we discuss some of the major developments that have occurred in the field of central auditory assessment over the past 30 years. We discuss both the psychophysical and the electrophysiological procedures that have been used for either research and/or clinical purposes. Case illustrations from our own clinical experience are also provided. Finally, we conclude by suggesting directions for future research.

Central auditory function following anterior sectioning of the corpus callosum

This paper describes auditory findings for eight patients with anterior sections of the corpus callosum. Peripheral (pure tone and speech recognition) and five central auditory tests were administered to each of the eight patients prior to surgery and then again approximately 2 weeks after surgery. The central tests administered included a low-pass filtered speech test, the frequency patterns perception test, and three dichotic speech tests. Mean scores for the peripheral tests fell grossly within the normal range preoperatively and showed little change postoperatively. Similarly, scores on the central tests, though somewhat more variable, did not show any obvious differences upon pre- and postsurgical comparison. A comparison of these results with those reported previously for patients with complete commissurotomies (Musiek, Kibbe, and Baran. Semin Hear 1984;5:219-29) revealed that as a group, patients with anterior sections of the corpus callosum showed fewer postsurgery deficits than did the subjects with complete commissurotomies. The lack of an apparent auditory effect in the anterior group is believed to have an anatomical basis.

Neuroanatomy, neurophysiology, and central auditory assessment. Part I: Brain stem

This paper is the first in a series of three that address neuroanatomical and neurophysiological aspects of central auditory assessment. The focus of this article is the "auditory" brain stem. Pictures of the auditory structures in the human brain stem in normal and pathological states are shown. Physiological evidence of neural coding of acoustic stimuli is discussed. Relationships between brain stem anatomy/physiology and clinical test results and their interpretation are highlighted.

Release from central auditory competition in the split-brain patient

We used dichotic digits (DD), staggered spondaic words (SSW), and frequency patterns (PATT) to study central auditory function before and after two-stage callosotomy. Preoperatively, the patient demonstrated reduced scores bilaterally on all these tests, consistent with documented bilateral hemisphere lesions. After the first operation (sectioning the posterior half of the corpus callosum), the dichotic tests (DD and SSW) revealed the expected decrease in left-ear scores, but there was improvement on the right, perhaps because there was release from central auditory competition. Our findings also suggest that the "auditory" portion of the corpus callosum may be in the posterior half of this structure.