Automatic classification of 6-month-old infants at familial risk for language-based learning disorder using a support vector machine

AbstractObjectivesThis study assesses the ability of a novel, “automatic classification” approach to facilitate identification of infants at highest familial risk for language-learning disorders (LLD) and to provide converging assessments to enable earlier detection of developmental disorders that disrupt language acquisition.MethodsNetwork connectivity measures derived from 62-channel electroencephalogram (EEG) recording were used to identify selected features within two infant groups who differed on LLD risk: infants with a family history of LLD (FH+) and typically-developing infants without such a history (FH−). A support vector machine was deployed; global efficiency and global and local clustering coefficients were computed. A novel minimum spanning tree (MST) approach was also applied. Cross-validation was employed to assess the resultant classification.ResultsInfants were classified with about 80% accuracy into FH+ and FH− groups with 89% specificity and precision of 92%. Clustering patterns differed by risk group and MST network analysis suggests that FH+ infants’ EEG complexity patterns were significantly different from FH− infants.ConclusionsThe automatic classification techniques used here were shown to be both robust and reliable and should provide valuable information when applied to early identification of risk or clinical groups.SignificanceThe ability to identify infants at highest risk for LLD using “automatic classification” strategies is a novel convergent approach that may facilitate earlier diagnosis and remediation

Effects of Presentation Rate and Attention on Auditory Discrimination: A Comparison of Long-Latency Auditory Evoked Potentials in School-Aged Children and Adults.

Decoding human speech requires both perception and integration of brief, successive auditory stimuli that enter the central nervous system as well as the allocation of attention to language-relevant signals. This study assesses the role of attention on processing rapid transient stimuli in adults and children. Cortical responses (EEG/ERPs), specifically mismatch negativity (MMN) responses, to paired tones (standard 100-100 Hz; deviant 100-300 Hz) separated by a 300, 70 or 10 ms silent gap (ISI) were recorded under Ignore and Attend conditions in 21 adults and 23 children (6-11 years old). In adults, an attention-related enhancement was found for all rate conditions and laterality effects (L>R) were observed. In children, 2 auditory discrimination-related peaks were identified from the difference wave (deviant-standard): an early peak (eMMN) at about 100-300 ms indexing sensory processing, and a later peak (LDN), at about 400-600 ms, thought to reflect reorientation to the deviant stimuli or "second-look" processing. Results revealed differing patterns of activation and attention modulation for the eMMN in children as compared to the MMN in adults: The eMMN had a more frontal topography as compared to adults and attention played a significantly greater role in childrens' rate processing. The pattern of findings for the LDN was consistent with hypothesized mechanisms related to further processing of complex stimuli. The differences between eMMN and LDN observed here support the premise that separate cognitive processes and mechanisms underlie these ERP peaks. These findings are the first to show that the eMMN and LDN differ under different temporal and attentional conditions, and that a more complete understanding of children's responses to rapid successive auditory stimulation requires an examination of both peaks

Oscillatory Dynamics Underlying Perceptual Narrowing of Native Phoneme Mapping from 6 to 12 Months of Age

During the first months of life, human infants process phonemic elements from all languages similarly. However, by 12 months of age, as language-specific phonemic maps are established, infants respond preferentially to their native language. This process, known as perceptual narrowing, supports neural representation and thus efficient processing of the distinctive phonemes within the sound environment. Although oscillatory mechanisms underlying processing of native and non-native phonemic contrasts were recently delineated in 6-month-old infants, the maturational trajectory of these mechanisms remained unclear. A group of typically developing infants born into monolingual English families, were followed from 6 to 12 months and presented with English and Spanish syllable contrasts varying in voice-onset time. Brain responses were recorded with high-density electroencephalogram, and sources of event-related potential generators identified at right and left auditory cortices at 6 and 12 months and also atfrontal cortex at 6 months. Time-frequency analyses conducted at source level found variations in both ! and " ranges across age. Compared with 6-month-olds, 12-month-olds’ responses to native phonemes showed smaller and faster phase synchronization and less spectral power in the ! range, and increases in left phase synchrony as well as induced high-" activity in both frontal and left auditory sources. These results demonstrate that infants become more automatized and efficient in processing their native language as they approach 12 months of age via the interplay between ! and " oscillations. We suggest that, while ! oscillations support syllable processing, " oscillations underlie phonemic perceptual narrowing, progressively favoring mapping of native over non-native language across the first year of life.peerReviewe

Children <i>Attend</i> Condition.

<p>Grand average ERP’s of children for the <i>Attend</i> condition at Fc₃ (Ch. 17) and Fc₄ (Ch. 54) for 300ms (top), 70ms (middle) and 10ms (bottom) ISI’s are shown. Response to the standard stimuli (blue line), the deviant stimuli (red line) and the difference condition (standard- deviant; green line) are plotted. Vertical pink bars on the baseline indicate the onset of the tones. Tone 1 and tone 2 are paired stimuli. Negative voltages are plotted up, positive voltages are plotted down.</p

Means and Standard Deviations of the Late Difference Negativity (LDN) Amplitude (mV) in the <i>Ignore</i> and <i>Attend</i> condition for Children.

<p>Means and Standard Deviations of the Late Difference Negativity (LDN) Amplitude (mV) in the <i>Ignore</i> and <i>Attend</i> condition for Children.</p

Adult <i>Attend</i> grand averaged topographic maps.

<p>Whole-head topographies for grand average waveforms for the <i>Attend</i> condition at Fc₃ (Ch 17) and Fc₄ (Ch 54) for 300ms (top), 70ms (middle) and 10ms (bottom) ISI’s are shown. Negativity up, positivity down. The standard wave is shown in blue, deviant in red, and difference (deviant-standard) in green. (deviant-standard) in green. Vertical bars on the baseline indicate the onset of the tones. Tone 1 and tone 2 are paired stimuli.</p

Adult <i>Ignore</i> Condition.

<p>Grand average ERP’s of the adults for the <i>Ignore</i> condition at Fc₃ (Ch.17) and Fc₄ (Ch.54) for 300ms (top), 70ms (middle) and 10ms (bottom) ISI’s are shown. Response to the standard stimuli (blue line), the deviant stimuli (red line) and the difference condition (standard- deviant; green line) are plotted. Vertical pink bars on the baseline indicate the onset of the tones. Tone 1 and tone 2 are paired stimuli. Negative voltages are plotted up, positive voltages are plotted down.</p

Adult <i>Attend</i> Condition.

<p>Grand average ERP’s of the adults for the <i>Attend</i> condition at Fc₃ (Ch 17) and Fc₄ (Ch 54) for 300ms (top), 70ms (middle) and 10ms (bottom) ISI’s are shown. Response to the standard stimuli (blue line), the deviant stimuli (red line) and the difference condition (standard- deviant; green line) are plotted. Vertical pink bars on the baseline indicate the onset of the tones. Tone 1 and tone 2 are paired stimuli. Negative voltages are plotted up, positive voltages are plotted down.</p