Phase Alignment of Low-Frequency Neural Activity to the Amplitude Envelope of Speech Reflects Evoked Responses to Acoustic Edges, Not Oscillatory Entrainment.

The amplitude envelope of speech is crucial for accurate comprehension. Considered a key stage in speech processing, the phase of neural activity in the theta-delta bands (1-10 Hz) tracks the phase of the speech amplitude envelope during listening. However, the mechanisms underlying this envelope representation have been heavily debated. A dominant model posits that envelope tracking reflects entrainment of endogenous low-frequency oscillations to the speech envelope. Alternatively, envelope tracking reflects a series of evoked responses to acoustic landmarks within the envelope. It has proven challenging to distinguish these two mechanisms. To address this, we recorded MEG while participants (n = 12, 6 female) listened to natural speech, and compared the neural phase patterns to the predictions of two computational models: an oscillatory entrainment model and a model of evoked responses to peaks in the rate of envelope change. Critically, we also presented speech at slowed rates, where the spectro-temporal predictions of the two models diverge. Our analyses revealed transient theta phase-locking in regular speech, as predicted by both models. However, for slow speech, we found transient theta and delta phase-locking, a pattern that was fully compatible with the evoked response model but could not be explained by the oscillatory entrainment model. Furthermore, encoding of acoustic edge magnitudes was invariant to contextual speech rate, demonstrating speech rate normalization of acoustic edge representations. Together, our results suggest that neural phase-locking to the speech envelope is more likely to reflect discrete representation of transient information rather than oscillatory entrainment.SIGNIFICANCE STATEMENT This study probes a highly debated topic in speech perception: the neural mechanisms underlying the cortical representation of the temporal envelope of speech. It is well established that the slow intensity profile of the speech signal, its envelope, elicits a robust brain response that "tracks" these envelope fluctuations. The oscillatory entrainment model posits that envelope tracking reflects phase alignment of endogenous neural oscillations. Here the authors provide evidence for a distinct mechanism. They show that neural speech envelope tracking arises from transient evoked neural responses to rapid increases in the speech envelope. Explicit computational modeling provides direct and compelling evidence that evoked responses are the primary mechanism underlying cortical speech envelope representations, with no evidence for oscillatory entrainment.

Childhood Listening and Associated Cognitive Difficulties Persist Into Adolescence.

OBJECTIVE: Listening difficulty (LiD) refers to the challenges individuals face when trying to hear and comprehend speech and other sounds. LiD can arise from various sources, such as hearing sensitivity, language comprehension, cognitive function, or auditory processing. Although some children with LiD have hearing loss, many have clinically normal audiometric thresholds. To determine the impact of hearing and cognitive factors on LiD in children with a clinically normal audiogram, we conducted a longitudinal study. The Evaluation of Children's Listening & Processing Skills (ECLiPS), a validated and standardized caregiver evaluation tool, was used to group participants as either LiD or typically developing (TD). Our previous study aimed to characterize LiD in 6- to 13-year-old children during the project's baseline, cross-sectional phase. We found that children with LiD needed a higher signal-to-noise ratio during speech-in-speech tests and scored lower on all assessed components of the NIH Cognition Toolbox than TD children. The primary goal of this study was to examine if the differences between LiD and TD groups are temporary or enduring throughout childhood. DESIGN: This longitudinal study had three data collection waves for children with LiD and TD aged 6 to 13 years at Wave 1, followed by assessments at 2-year (Wave 2) and 4-year (Wave 3) intervals. Primary analysis focused on data from Waves 1 and 2. Secondary analysis encompassed all three waves despite high attrition at Wave 3. Caregivers completed the ECLiPS, while participants completed the Listening in Spatialized Noise-Sentences (LiSN-S) test and the NIH-Toolbox Cognition Battery during each wave. The analysis consisted of (1) examining longitudinal differences between TD and LiD groups in demographics, listening, auditory, and cognitive function; (2) identifying functional domains contributing to LiD; and (3) test-retest reliability of measures across waves. Mixed-effect models were employed to analyze longitudinal data. RESULTS: The study enrolled 169 participants, with 147, 100, and 31 children completing the required testing during Waves 1, 2, and 3, respectively. The mean ages at these waves were 9.5, 12.0, and 14.0 years. On average, children with LiD consistently underperformed TD children in auditory and cognitive tasks across all waves. Maternal education, auditory, and cognitive abilities independently predicted caregiver-reported listening skills. Significant correlations between Waves 1 and 2 confirmed high, long-term reliability. Secondary analysis of Wave 3 was consistent with the primary analyses of Waves 1 and 2, reinforcing the enduring nature of listening difficulties. CONCLUSION: Children with LiD and clinically normal audiograms experience persistent auditory, listening, and cognitive challenges through at least adolescence. The degree of LiD can be independently predicted by maternal education, cognitive processing, and spatial listening skills. This study underscores the importance of early detection and intervention for childhood LiD and highlights the role of socioeconomic factors as contributors to these challenges.

The Current State of Neonatal Neurodevelopmental Follow-up Programs in North America: A Children's Hospitals Neonatal Consortium Report.

OBJECTIVE: This study aimed to determine neonatal neurodevelopmental follow-up (NDFU) practices across academic centers. STUDY DESIGN: This study was a cross-sectional survey that addressed center-specific neonatal NDFU practices within the Children's Hospitals Neonatal Consortium (CHNC). RESULTS: Survey response rate was 76%, and 97% of respondents had a formal NDFU program. Programs were commonly staffed by neonatologists (80%), physical therapists (77%), and nurse practitioners (74%). Median gestational age at birth identified for follow-up was ≤32 weeks (range 26-36). Median duration was 3 years (range 2-18). Ninety-seven percent of sites used Bayley Scales of Infant and Toddler Development, but instruments used varied across ages. Scores were recorded in discrete electronic data fields at 43% of sites. Social determinants of health data were collected by 63%. Care coordination and telehealth services were not universally available. CONCLUSION: NDFU clinics are almost universal within CHNC centers. Commonalities and variances in practice highlight opportunities for data sharing and development of best practices. KEY POINTS: · Neonatal NDFU clinics help transition high-risk infants home.. · Interdisciplinary neonatal intensive care unit follow-up brings together previously separated outpatient service lines.. · This study reviews the current state of neonatal NDFU in North America..

Three- and four-dimensional mapping of speech and language in patients with epilepsy.

We have provided 3-D and 4D mapping of speech and language function based upon the results of direct cortical stimulation and event-related modulation of electrocorticography signals. Patients estimated to have right-hemispheric language dominance were excluded. Thus, 100 patients who underwent two-stage epilepsy surgery with chronic electrocorticography recording were studied. An older group consisted of 84 patients at least 10 years of age (7367 artefact-free non-epileptic electrodes), whereas a younger group included 16 children younger than age 10 (1438 electrodes). The probability of symptoms transiently induced by electrical stimulation was delineated on a 3D average surface image. The electrocorticography amplitude changes of high-gamma (70-110 Hz) and beta (15-30 Hz) activities during an auditory-naming task were animated on the average surface image in a 4D manner. Thereby, high-gamma augmentation and beta attenuation were treated as summary measures of cortical activation. Stimulation data indicated the causal relationship between (i) superior-temporal gyrus of either hemisphere and auditory hallucination; (ii) left superior-/middle-temporal gyri and receptive aphasia; (iii) widespread temporal/frontal lobe regions of the left hemisphere and expressive aphasia; and (iv) bilateral precentral/left posterior superior-frontal regions and speech arrest. On electrocorticography analysis, high-gamma augmentation involved the bilateral superior-temporal and precentral gyri immediately following question onset; at the same time, high-gamma activity was attenuated in the left orbitofrontal gyrus. High-gamma activity was augmented in the left temporal/frontal lobe regions, as well as left inferior-parietal and cingulate regions, maximally around question offset, with high-gamma augmentation in the left pars orbitalis inferior-frontal, middle-frontal, and inferior-parietal regions preceded by high-gamma attenuation in the contralateral homotopic regions. Immediately before verbal response, high-gamma augmentation involved the posterior superior-frontal and pre/postcentral regions, bilaterally. Beta-attenuation was spatially and temporally correlated with high-gamma augmentation in general but with exceptions. The younger and older groups shared similar spatial-temporal profiles of high-gamma and beta modulation; except, the younger group failed to show left-dominant activation in the rostral middle-frontal and pars orbitalis inferior-frontal regions around stimulus offset. The human brain may rapidly and alternately activate and deactivate cortical areas advantageous or obtrusive to function directed toward speech and language at a given moment. Increased left-dominant activation in the anterior frontal structures in the older age group may reflect developmental consolidation of the language system. The results of our functional mapping may be useful in predicting, across not only space but also time and patient age, sites specific to language function for presurgical evaluation of focal epilepsy.

Corpus Callosum Abnormalities at Term-Equivalent Age Are Associated with Language Development at 2 Years' Corrected Age in Infants Born Very Preterm.

We studied the effect of microstructural abnormalities in the corpus callosum on language development in 348 infants born very prematurely. We discovered that the fractional anisotropy of the corpus callosum anterior midbody was a significant predictor of standardized language scores at 2 years, independent of clinical and social risk factors.

Human occipital cortices differentially exert saccadic suppression: Intracranial recording in children.

By repeating saccades unconsciously, humans explore the surrounding world every day. Saccades inevitably move external visual images across the retina at high velocity; nonetheless, healthy humans don't perceive transient blurring of the visual scene during saccades. This perceptual stability is referred to as saccadic suppression. Functional suppression is believed to take place transiently in the visual systems, but it remains unknown how commonly or differentially the human occipital lobe activities are suppressed at the large-scale cortical network level. We determined the spatial-temporal dynamics of intracranially-recorded gamma activity at 80-150 Hz around spontaneous saccades under no-task conditions during wakefulness and those in darkness during REM sleep. Regardless of wakefulness or REM sleep, a small degree of attenuation of gamma activity was noted in the occipital regions during saccades, most extensively in the polar and least in the medial portions. Longer saccades were associated with more intense gamma-attenuation. Gamma-attenuation was subsequently followed by gamma-augmentation most extensively involving the medial and least involving the polar occipital region. Such gamma-augmentation was more intense during wakefulness and temporally locked to the offset of saccades. The polarities of initial peaks of perisaccadic event-related potentials (ERPs) were frequently positive in the medial and negative in the polar occipital regions. The present study, for the first time, provided the electrophysiological evidence that human occipital cortices differentially exert perisaccadic modulation. Transiently suppressed sensitivity of the primary visual cortex in the polar region may be an important neural basis for saccadic suppression. Presence of occipital gamma-attenuation even during REM sleep suggests that saccadic suppression might be exerted even without external visual inputs. The primary visual cortex in the medial region, compared to the polar region, may be more sensitive to an upcoming visual scene provided at the offset of each saccade.

Young athlete with sudden cardiac arrest treated with therapeutic hypothermia.

Reported herein is a coronary anomaly that occurred in a young adolescent athlete who presented with cardiopulmonary arrest. The patient was resuscitated and treated with therapeutic hypothermia. The patient had no associated neurological complications at follow up. Enhanced computed tomography of the heart indicated an anomalous left main coronary artery originating from the right coronary sinus and coursing between the aorta and the pulmonary artery. The patient underwent surgical intervention with coronary artery bypass grafting to prevent symptom recurrence.

Early surgery in very preterm infants is associated with brain abnormalities on term MRI: a propensity score analysis.

OBJECTIVE: To investigate the association between exposure to surgery under general anesthesia and brain abnormalities and neurodevelopmental outcomes in very preterm infants. STUDY DESIGN: This prospective observational study includes 392 infants born at or below 32 weeks' gestational age. Participants completed brain MRI at term-equivalent age and Bayley-III assessment at 2 years corrected age. We evaluated the independent effects of surgery on brain MRI abnormalities and neurodevelopmental outcomes after propensity score matching. RESULTS: All infants completed brain MRI, and 341 (87%) completed neurodevelopmental testing. Forty-five received surgery. Surgery was associated with worse MRI abnormalities (p < 0.0001) but with none of the developmental outcomes after propensity score matching. The global brain abnormality score was associated with the Bayley Cognitive (p = 0.005) and Motor (p = 0.028) composite scores. CONCLUSIONS: Very preterm infants exposed to surgery under general anesthesia were at higher risk of brain abnormalities on MRI at term.

Corpus callosum abnormalities at term-equivalent age are associated with language development at two years corrected age in infants born very preterm.

We studied the impact of microstructural abnormalities in the corpus callosum on language development in 348 infants born very prematurely. We discovered that the fractional anisotropy of the corpus callosum anterior midbody was a significant predictor of standardized language scores at two years, independent of clinical and social risk factors.

Cooing- and babbling-related gamma-oscillations during infancy: intracranial recording.

We determined the spatio-temporal dynamics of intracranially-recorded gamma-oscillations modulated by spontaneous cooing and babbling, which are considered to embody pre-linguistic language behaviors during infancy. Electrocorticographic (ECoG) signals were recorded from 110 cortical sites in the right hemisphere of a 10-month-old girl with focal epilepsy. Electrocorticographic signals were time-locked to the onset of cooing or babbling. The amplitudes of gamma-oscillations during vocalizations were compared to those during preceding silent reference periods. Cooing and babbling elicited significant gamma-augmentation at 30-100 Hz at distinct sites of the inferior Rolandic region, whereas both forms of vocalizations elicited gamma-augmentation at an identical superior temporal site. The spatial, temporal and spectral characteristics of gamma-augmentation elicited by cooing and babbling were similar to those elicited by phoneme vocalization in older children and adults. Differential activation within the right inferior Rolandic region during cooing and babbling may reflect the mechanical or developmental difference between these two forms of vocalizations. The right superior temporal gyrus may participate in an auditory feedback system during vocalization.

[A case of gas-forming pyogenic liver abscess].

A 62-year-old man with a 20-year history of diabetes mellitus presented with appetite loss was found and a large niveau was found in the right subphrenic space on abdominal X-ray film. Ultrasonography and computed tomography showed a large hepatic abscess with gas formation and cholecystitis with a gallstone. Klebsiella pneumoniae was isolated from the abscess, which communicated with the bile duct and was treated with antibiotics and percutaneous drainage. It should thus be noted that increased anaerobic catabolism by microbes and impaired transport of end products may cause gas-formation in patients with diabetes mellitus.

The high prevalence of inappropriate feeding among infants presenting with an apparent life-threatening event.

Kojima K, Mckinley K, Donohue P, Sigal Y. The high prevalence of inappropriate feeding among infants presenting with an apparent life-threatening event. Turk J Pediatr 2017; 59: 304-310. Although there are anecdotal reports of a link between inappropriate feeding and an apparent life-threatening event (ALTE), previous studies have not examined this association in a cohort of affected infants. This study compared the feeding behaviors of infants who have had an ALTE with age- and sex-matched controls. This is a single-center case control study. Forty-six term infants aged 6 months or less, who were hospitalized over a 34-month period following an ALTE, comprised the study sample; 92 age- and sex-matched controls were recruited from a wellness clinic. Feeding practices reported by parents were evaluated for their appropriateness with respect to the volume of each feeding, and the frequency and total volume of feedings per 24-hour period, based on the American Academy of Pediatrics guidelines. Comparisons were made between the ALTE cases and controls. Inappropriately fed infants were compared with the rest of the sample. The ALTE and control groups were similar with respect to the prevalence of breastfeeding, insurance, birth weight, and weight percentile at presentation. The ALTE group had a lower prevalence of appropriate feeding compared to the control group (43.5% versus 63.0%, p = 0.029). Overfed infants were at a higher weight percentile at the time of presentation (46.5th percentile versus 31.4 < sup > th < /sup > percentile, p = 0.037). These results represent the association between ALTE and inappropriate feeding practice, which emphasizes the need for assessment and education regarding feeding practices in patient presenting with an ALTE.

Paravertebral calcification as a potential indicator for nonaccidental trauma.

We report a case of nonaccidental trauma (NAT) involving a 23-month-old boy who presented with seizures, acute subarachnoid hemorrhage, and acute subdural hemorrhage. Ophthalmologic examination showed bilateral intraretinal hemorrhages. Further evaluation revealed that he had bilateral thoracolumbar paravertebral calcifications. The Children's Protective Services agency was involved in the case. The child was discharged to an inpatient rehabilitation facility. Vertebral fracture associated with paravertebral calcification has been reported as a sign of NAT. This case was unique because our patient had paravertebral calcifications without vertebral fracture. Paravertebral calcification alone could serve as an indicator of NAT.

Mapping mental calculation systems with electrocorticography.

OBJECTIVE: We investigated intracranially-recorded gamma activity during calculation tasks to better understand the cortical dynamics of calculation. METHODS: We studied 11 patients with focal epilepsy (age range: 9-28years) who underwent measurement of calculation- and naming-related gamma-augmentation during extraoperative electrocorticography (ECoG). The patients were instructed to overtly verbalize a one-word answer in response to auditorily-delivered calculation and naming questions. The assigned calculation tasks were addition and subtraction involving integers between 1 and 17. RESULTS: Out of the 1001 analyzed cortical electrode sites, 63 showed gamma-augmentation at 50-120Hz elicited by both tasks, 88 specifically during naming, and 7 specifically during calculation. Common gamma-augmentation mainly took place in the Rolandic regions. Calculation-specific gamma-augmentation, involving the period between the question-offset and response-onset, was noted in the middle-temporal, inferior-parietal, inferior post-central, middle-frontal, and premotor regions of the left hemisphere. Calculation-specific gamma-augmentation in the middle-temporal, inferior-parietal, and inferior post-central regions peaked around the question offset, while that in the frontal lobe peaked after the question offset and before the response onset. This study failed to detect a significant difference in calculation-specific gamma amplitude between easy trials and difficult ones requiring multi-digit operations. CONCLUSIONS: Auditorily-delivered stimuli can elicit calculation-specific gamma-augmentation in multiple regions of the left hemisphere including the parietal region. However, the additive diagnostic value of measurement of gamma-augmentation related to a simple calculation task appears modest. SIGNIFICANCE: Further studies are warranted to determine the functional significance of calculation-specific gamma-augmentation in each site, and to establish the optimal protocol for mapping mental calculation.

Gamma activity modulated by naming of ambiguous and unambiguous images: intracranial recording.

OBJECTIVE: Humans sometimes need to recognize objects based on vague and ambiguous silhouettes. Recognition of such images may require an intuitive guess. We determined the spatial-temporal characteristics of intracranially-recorded gamma activity (at 50-120Hz) augmented differentially by naming of ambiguous and unambiguous images. METHODS: We studied 10 patients who underwent epilepsy surgery. Ambiguous and unambiguous images were presented during extraoperative electrocorticography recording, and patients were instructed to overtly name the object as it is first perceived. RESULTS: Both naming tasks were commonly associated with gamma-augmentation sequentially involving the occipital and occipital-temporal regions, bilaterally, within 200ms after the onset of image presentation. Naming of ambiguous images elicited gamma-augmentation specifically involving portions of the inferior-frontal, orbitofrontal, and inferior-parietal regions at 400ms and after. Unambiguous images were associated with more intense gamma-augmentation in portions of the occipital and occipital-temporal regions. CONCLUSIONS: Frontal-parietal gamma-augmentation specific to ambiguous images may reflect the additional cortical processing involved in exerting intuitive guess. Occipital gamma-augmentation enhanced during naming of unambiguous images can be explained by visual processing of stimuli with richer detail. SIGNIFICANCE: Our results support the theoretical model that guessing processes in visual domain occur following the accumulation of sensory evidence resulting from the bottom-up processing in the occipital-temporal visual pathways.

Electrocorticographic correlates of overt articulation of 44 English phonemes: intracranial recording in children with focal epilepsy.

OBJECTIVE: We determined the temporal-spatial patterns of electrocorticography (ECoG) signal modulation during overt articulation of 44 American English phonemes. METHODS: We studied two children with focal epilepsy who underwent extraoperative ECoG recording. Using animation movies, we delineated 'when' and 'where' gamma- (70-110 Hz) and low-frequency-band activities (10-30 Hz) were modulated during self-paced articulation. RESULTS: Regardless of the classes of phoneme articulated, gamma-augmentation initially involved a common site within the left inferior Rolandic area. Subsequently, gamma-augmentation and/or attenuation involved distinct sites within the left oral-sensorimotor area with a timing variable across phonemes. Finally, gamma-augmentation in a larynx-sensorimotor area took place uniformly at the onset of sound generation, and effectively distinguished voiced and voiceless phonemes. Gamma-attenuation involved the left inferior-frontal and superior-temporal regions simultaneously during articulation. Low-frequency band attenuation involved widespread regions including the frontal, temporal, and parietal regions. CONCLUSIONS: Our preliminary results support the notion that articulation of distinct phonemes recruits specific sensorimotor activation and deactivation. Gamma attenuation in the left inferior-frontal and superior-temporal regions may reflect transient functional suppression in these cortical regions during automatic, self-paced vocalization of phonemes containing no semantic or syntactic information. SIGNIFICANCE: Further studies are warranted to determine if measurement of event-related modulations of gamma-band activity, compared to that of the low-frequency-band, is more useful for decoding the underlying articulatory functions.

Predicting outcomes of neonates born to GBS-positive women who received inadequate intrapartum antimicrobial prophylaxis.

We determined the predicting factors of early-onset group B streptococcal (EOGBS) infection in neonates who were born to GBS carrier mothers with inadequate intrapartum antibiotic prophylaxis (IAP). Medical records of all neonates born from January 1, 2008 to April 1, 2010 were reviewed. Inadequate IAP was defined as delivery less than 4 hours (h) after the first administration of antimicrobial. Of 1910 neonates, 273 were born from mothers colonized with GBS, including 69 who received inadequate IAP. Of 69 neonates, nine showed symptoms, including respiratory distress, fever, tachycardia, vomiting, and irritability. Abnormalities in complete blood count (CBC) and C-reactive protein (CRP) were noted in three and four neonates, respectively. Three infants were diagnosed with EOGBS infection confirmed by positive rectal and throat cultures, and all three presented with respiratory distress and CRP abnormalities. Respiratory distress (p=0.0004) and CRP (p=0.0001) offered reliable indicators for detecting EOGBS infections.

Animal category-preferential gamma-band responses in the lower- and higher-order visual areas: intracranial recording in children.

OBJECTIVE: We determined where and when category-preferential augmentation of gamma activity took place during naming of animal or non-animal pictures. METHODS: We studied 41 patients with focal epilepsy who underwent measurement of naming-related gamma-augmentation at 50-120 Hz during extraoperative electrocorticography. The assigned task consisted of naming of a visually-presented object classified as either 'animal' or 'non-animal'. RESULTS: Within 80 ms following the onset of picture presentation, regardless of stimulus type, gamma-activity in bilateral occipital regions began to be augmented compared to the resting period. Initially in the occipital poles (at 140 ms and after) and subsequently in the lateral, inferior and medial occipital regions (at 320 ms and after), the degree of gamma-augmentation elicited by 'animal naming' became larger (by up to 52%) than that by 'non-animal naming'. Immediately prior to the overt response, left inferior frontal gamma-augmentation became modestly larger during 'animal naming' compared to 'non-animal naming'. CONCLUSIONS: Animal category-preferential gamma-augmentation sequentially involved the lower- and higher-order visual areas. Relatively larger occipital gamma-augmentation during 'animal naming' can be attributed to the more attentive analysis of animal stimuli including the face. Animal-preferential gamma-augmentation in the left inferior frontal region could be attributed to a need for selective semantic retrieval during 'animal naming'. SIGNIFICANCE: A specific program of cortical processing to distinguish an animal (or face) from other objects might be initiated in the lower-order visual cortex.