BioMAP is now BioMARK
BioMARK (Biological Marker of Auditory Processing, formerly known as BioMAP),objectively assesses the neural processing of sound. Unlike traditional brainstem evoked response recordings using clicks or tone bursts, BioMARK uses a speech syllable that reflects the acoustic characteristics of sounds that present difficulties for some individuals with reading and auditory processing disorders. Over the past decade Dr. Nina Kraus and her colleagues at the Auditory Neuroscience Lab at Northwestern University have evaluated the speech evoked brainstem responses of more than 1000 children, and have discovered that these responses act as a unique biological marker for those learning impaired children with disordered auditory processing who have a high likelihood of benefiting from an auditory training program. As a supplement to diagnostic tools typical of clinical assessment, BioMARK provides a measure that is objective and non-invasive, enabling professionals to more fully assess auditory function.
Natus Medical Incorporated has commercialized BioMARK outside the U.S.* as a clinical tool for the assessment of children with auditory processing disorders, which can include a range of educational diagnoses such as dyslexia, auditory processing disorders (APD), specific language impairment (SLI) and learning disability (LD).
Background
Children and adults diagnosed with reading and auditory processing disorders (including trouble hearing in noise) exhibit highly variable perceptual and cognitive profiles. Many factors can contribute to clinical assessment. These include variations in basic perceptual physiology, higher levels of cognitive function such as memory and attention, experientially developed compensatory mechanisms, exposure to previous remedial interventions and differing interpretations of assessment outcomes and diagnostic categories by clinicians.
The remediation of children with reading and listening disorders involves numerous clinical approaches. There are a number of promising intervention paradigms that utilize auditory training . BioMARK offers an important set of biological measures that can be used with other tests for assessing the efficacy of auditory training and allows for a determination of which children are the best candidates for such training.
Description
Accurate representation of stimulus timing in the auditory brainstem is a hallmark of normal perception. Recording the brainstem's response to sound has long been established as a valid and reliable means of assessing the integrity of the neural transmission of acoustic stimuli. Transient acoustic events induce a pattern of voltage fluctuations in the brainstem, which can be measured with scalp electrodes resulting in a waveform yielding information about brainstem nuclei along the ascending central auditory pathway. Disruptions in this systematic progression on the order of fractions of milliseconds are clinically significant in the diagnosis of hearing loss and brainstem pathology.
To further our understanding of the functional relationship between the acoustic structure of speech and the brainstem’s response, we have developed a means by which to characterize the neural activity of the brainstem in response to the speech sound /da/ (figure).Measures of timing and magnitude are used to describe brainstem neural activity to speech, which is characterized by rapid temporal changes and complex spectral distributions. Timing measures provide insight into (1) the accuracy with which brainstem nuclei synchronously respond to acoustic stimuli (e.g., peak latency, inter-peak interval, and slope), and (2) the fidelity with which the response mimics either the stimulus or another response (e.g., stimulus-to-response correlations, and inter-response correlations). Magnitude measures provide information about (1) the robustness with which the brainstem nuclei respond to acoustic stimuli and (2) the size of a given spectral component within the response.
A growing body of literature indicates that brainstem measures relating to the encoding of linguistic information can serve as a biological marker for auditory function in individuals with language-based learning problems, such as dyslexia. A consistent finding is that some children with language-based learning problems and difficulty hearing speech in noisy situations exhibit a unique pattern of auditory neural activity that easily distinguishes them from the larger population of children with learning problems.
From this basic research we have developed a method to assess whether children with reading and listening disorders have preconscious, subcortical, disordered neural "transcription" of sound. We have found that learning disabled children with brainstem deficits have a high likelihood of benefiting from an auditory training program.
Clinical Application
To date, there has been no electrophysiological test in the clinical test battery to objectively assess the neural transcription of speech sounds. Traditionally, auditory processing evaluations have consisted of behavioral measures that are subjective in nature and include non-perceptual variables (e.g., motivation, failure to understand the task, unreliability, etc.). Just as electrophysiological testing has become an important tool in the assessment of peripheral hearing, the availability of a clinical assessment tool that is objective (does not rely on the listener's response) and non-invasive, enables professionals to assess more fully the auditory processing abilities of children, in particular children with central auditory processing and learning disabilities (e.g., dyslexia). Brainstem function can also be applied to assist in the selection of children who are candidates for auditory-based intervention training and to assess changes brought about by this training.
*Currently unavailable in the U.S. For questions about the Natus product that includes BioMARK, please contact Kathy Murphy, Global Marketing Manager, at kmurphy@natus.com.
Download the BioMARK packet for additional information.
For research underlying BioMARK, please refer to the following articles:
Chandrasekaran B, Hornickel J, Skoe E, Nicol T, Kraus N. (2009) Context-dependent encoding in the human auditory brainstem relates to hearing speech in noise: Implications for developmental dyslexia. Neuron 64:311-319.
Hornickel J, Skoe E, Nicol T, Zecker S, Kraus N. (2009) Subcortical Differentiation of Voiced Stop Consonants: Relationships to Reading and Speech in Noise Perception. Proceedings of the National Academy of Science 106(31): 13022–13027.
Tzounopoulos T, Kraus N. (2009) Learning To Encode Timing: Mechanisms of Plasticity in the Auditory Brainstem. Neuron.62(4): 463-469.
Krizman J, Skoe E, Kraus N. (in press) Stimulus rate and subcortical auditory processing of speech. Audiology Neurotology.
Hornickel JM, Skoe E, Kraus N. (2009) Subcortical lateralization of speech encoding. Audiology Neurotology. 14:198-207.
Russo NM, Nicol T, Trommer BL, Zecker S, Kraus N (2009) Brainstem transcription of speech is disrupted in children with autism spectrum disorders. Developmental Science 12(4):557–567.
Dhar S, Abel R, Hornickel J, Nicol T, Skoe E, Zhao W, Kraus N. (2009) Exploring the relationship between physiological measures of cochlear and brainstem function. Clinical Neurophysiology 120: 959-966.
Banai K, Hornickel JM, Skoe E, Nicol T, Zecker S, Kraus N (2009) Reading and Subcortical Auditory Function. Cerebral Cortex 19(11):2699-2707.
Johnson KL, Nicol T, Kraus N. (2008) Developmental plasticity in the human auditory brainstem Journal of Neuroscience 28(15):4000-4007.
Song JH, Banai K, Kraus N. (2008) Brainstem timing deficits in children with learning impairment may result from corticofugal origins. Audiology Neuro-Otolology 13:335-344.
Johnson K, Nicol T, Zecker S, Kraus N. (2007) Auditory brainstem correlates of perceptual timing deficits. Journal of Cognitive Neuroscience 19: 376 - 385.
Abrams A, Nicol T, Zecker S, Kraus N. (2006) Auditory brainstem timing predicts cerebral dominance for speech sounds. Journal of Neuroscience 26:11131 - 11137.
Song JH, Banai K, Russo NM, Kraus N. (2006) On the relationship between speech and nonspeech evoked auditory brainstem responses. Audiology Neuro-Otolology 11:233-241.
Banai K, Nicol T, Zecker S, Kraus N (2005) Brainstem timing: Implications for cortical processing and literacy. Journal of Neuroscience 25(43): 9850 - 9857.
Johnson KL, Nicol T & Kraus N (2005) The brainstem response to speech:a biological marker. Ear and Hearing 26(5): 424-433.
Kraus N & Nicol T (2005) Brainstem origins for cortical "what" and "'where" pathways in the auditory system. TRENDS in Neurosciences 28: 176 - 181.
Wible B, Nicol T, Kraus N. (2005) Correlation between brainstem and cortical auditory processes in normal and language-impaired children. Brain 128: 417 - 423.
Russo N, Nicol T, Musacchia G, Kraus, N. (2004) Brainstem responses to speech syllables.Clinical Neurophysiology115: 2021-2030.
Wible B, Nicol T & Kraus N. (2004) Atypical brainstem representation of onset and formant structure of speech sounds in children with language-based learning problems. Biological Psychology 67: 299-317.
Hayes E, Tiippana K, Nicol T, Sams M & Kraus, N. (2003) Integration of heard and seen speech: a factor in learning disabilities in children. Neuroscience Letters 351:46-50.
Cunningham J, Nicol T, King CD, Zecker SG & Kraus N. (2002) Effects of noise and cue enhancement on neural responses to speech in auditory midbrain, thalamus and cortex. Hearing Research 169:97-111.
Training
Song JH, Skoe E, Wong PCM, Kraus N. (2008) Plasticity in the adult human auditory brainstem following short-term linguistic training. Journal of Cognitive Neuroscience 20(10): 1892-1902.
Musacchia, G., Sams, M., Skoe, E., Kraus, N. (2007) Musicians have enhanced subcortical auditory and audiovisual processing of speech and music Proceedings of the National Academy of Sciences 104(40):15894-15898.
Wong PCM, Skoe E, Russo NM, Dees T, Kraus N. (2007) Musical experience shapes human brainstem encoding of linguistic pitch patterns. Nature Neuroscience10:420-422.
Russo N, Nicol T, Zecker S, Hayes E, Kraus N. (2005). Auditory training improves neural timing in the human brainstem. Behavioural Brain Research 156: 95-103.
Warrier CM, Johnson KL, Hayes E, Nicol T & Kraus N. (2004) Learning impaired children exhibit timing deficits and training-related improvements in auditory cortical responses to speech in noise. Experimental Brain Research 157: 431-441.
Hayes E, Warrier CM, Nicol T, Zecker SG & Kraus N. (2003) Neural plasticity following auditory training in children with learning problems. Clinical Neurophysiology 114:673-684.
King C, Warrier CM, Hayes E & Kraus N. (2002) Deficits in auditory brainstem encoding of speech sounds in children with learning problems. Neuroscience Letters 319:111-115.
Cunningham J, Nicol T, Zecker SG & Kraus N. (2001) Neurobiologic responses to speech in noise in children with learning problems: Deficits and strategies for improvement. Clinical Neurophysiology 112:758-767.
invited Reviews
Banai K & Kraus N (2008). The dynamic brainstem: implications for APD. In: D. McFarland and A. Cacace (eds). Current Controversies in Central Auditory Processing Disorder. Plural Publishing Inc: San Diego, CA. pp 269-289.
Kraus N & Nicol T (2009) Auditory evoked potentials. In Encyclopedia of Neuroscience, Binder MD, Hirokawa N, Windhorst U, eds., Springer: Berlin, pp 214-218.
Abrams D, Kraus N. (2009) Auditory pathway representation of speech sounds in humans. In: Handbook of Clinical Audiology, Katz J, Hood L, Burkard R, Medwetsky L (eds.). pp 611-626.
Kraus N, Banai K. (2007) Auditory processing malleability: Focus on language and music. Current Directions in Psychological Science, 16: 105-109.
Banai K and Kraus N. (2006) The neurobiology of central auditory processing disorder (CAPD), language impairment and learning disability. In: Handbook of Central Auditory Processing Disorder: From Science to Practice, G.D. Chermak, F.E. Musiek (eds), Plural Publishing Inc.
Wible B, Nicol T, Kraus N (2005) Encoding of complex sounds in an animal model: Implications for understanding speech perception in humans. In: Auditory Cortex: Towards a Synthesis of Human and Animal Research, Konig R, Heil P, Budinger E and Scheich H (eds.), Lawrence Erlbaum Associates, Oxford, pp 241-254.
Nicol T & Kraus N (2005) How can the neural encoding and perception of speech be improved? in:Plasticity and Signal Representation in the Auditory System, Merzenich M and Syka J(eds.) Springer, New York, pp 259-270.
Nicol T, Kraus N (2004) Speech-sound encoding: Physiological manifestations and behavioral ramifications.In: Clinical Neurophysiology Supplement 57: 624-630.
Kraus N & Nicol T. (2003) Aggregate neural responses to speech sounds in the central auditory system. Speech Communication 41:35-47.
