*BioMARK no longer commercialy available
BioMARK (Biological Marker of Auditory Processing) objectively assesses the neural processing of sound. Unlike traditional brainstem evoked response recordings using clicks or tone bursts, BioMARK uses a speech-like syllable with the acoustic characteristics of sounds that present difficulties for some individuals with reading, auditory processing disorders,and excesive difficulty hearing speech in noise. As a supplement to other clinical metrics, 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).
Children and adults 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.
A growing body of literature indicates that brainstem measures relating to the encoding of linguistic information can provide a biological metric of auditory function in individuals with language-based learning problems, such as dyslexia. Some children with language-based learning problems and difficulty hearing speech in noisy situations exhibit a unique pattern of auditory neural activity. Thus it is possible to determine whether children with reading and listening disorders have preconscious, subcortical, disordered neural transcription of sound. Research on animal models and human participants indicates that auditory brainstem functions can be moified with auditory training. The implication is that auditory training may enhance auditory function in clinical populations.
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 assessment of hearing loss and brainstem pathology.
The neural activity of the brainstem in response to the speech sound /da/ (figure) can be measured to further our understanding of the functional relationship between the acoustic structure of speech and the brainstem’s response. Measures of timing and magnitude are used to describe brainstem neural activity to speech, which consists of rapid temporal changes and complex spectral distributions. Timing measures reveal (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.
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 can be complicated by variables such as poor motivation, failure to understand the task, or distractability. 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 and non-invasive, enables professionals to more fully assess auditory function. Brainstem function can also be applied to assess biological changes brought about by remediation strategies.
*Currently unavailable in the U.S. For questions about the Natus product that includes BioMARK, please contact Jay O'Neal, firstname.lastname@example.org, 847-949-5200 ext 269.
For research underlying BioMARK, please refer to the following articles:
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.
Banai K, Hornickel JM, Skoe E, Nicol T, Zecker S, Kraus N. (2009) Reading and subcortical auditory function. Cerebral Cortex 19(11): 2699-2707.
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.
Abrams A, Nicol T, Zecker S, Kraus N. (2006) Auditory brainstem timing predicts cerebral dominance for speech sounds. Journal of Neuroscience 26: 11131-11137.
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.
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.
Banai K, Nicol T, Zecker S, Kraus N. (2005) Brainstem timing: Implications for cortical processing and literacy. Journal of Neuroscience 25(43): 9850-9857.
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 Neurophysiology 115: 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.
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.
Kraus N, Nicol T. (2005) Brainstem origins for cortical "what" and "'where" pathways in the auditory system. Trends in Neurosciences 28: 176-181.
Studies using BioMARK Stimulus
Song J, Nicol T, Kraus N. (2010) Test-Retest Reliability of the Speech-Evoked Auditory Brainstem Response. Clinical Neurophysiology, 122 (2011): pp. 346-355.
Krizman J, Skoe E, Kraus N. (2010) Stimulus rate and subcortical auditory processing of speech. Audiology Neurotology 15: 332-342.
Hornickel JM, Skoe E, Kraus N. (2009) Subcortical lateralization of speech encoding. Audiology Neurotology 14: 198-207.
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.
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, Russo NM, Kraus N. (2006) On the relationship between speech and nonspeech evoked auditory brainstem responses. Audiology Neuro-Otolology 11: 233-241.
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.
Johnson KL, Nicol T, Kraus N. (2005) The brainstem response to speech: a biological marker. Ear and Hearing 26(5): 424-433.
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.