Although awareness of concussion and mTBI is significantly growing in the general public, there is still no standardized, quantitative, biologically based methodology that is effective for assessing the impact of mild neuro-trauma. Current existing methods and products for this need are expensive, extremely slow, and in many cases fail to definitively and quantitatively diagnose the problem. For example, medical imaging technologies—though they are able to discern differences in subjects with traumatic brain injury —show few or no differences for mTBI or concussion, are costly (about $1K per scan), are not portable, and are not practical for getting a quick assessment.
The somatosensory system is uniquely suited for the design of a diagnostic system for overall cortical health for a number of reasons.
The somatotopic organization of the somatosensory system provides an ideal template for evoking cortical–cortical interactions in adjacent or near- adjacent cortical regions.
Ambient environmental noise in the system can be easily controlled (i.e., it is less likely that a patient will be exposed to distracting tactile input than auditory or visual input).
The somatosensory system is the only sensory system that is highly integrated with the pain system, and this is often an important aspect of a patient’s diagnosis.
A key concept in the model is that alterations in sensory percept occur in parallel with alterations in systemic cortical alterations, and “sampling” from the center of the brain (where the somatosensory cortex is located) is more analogous to obtaining a noninvasive biopsy of the cerebral cortex than any other sensory modality.
The Brain Gauge provides clinicians with invaluable information that can help take the guesswork out of concussion management and promote safe return-to-play decisions for athletes and return-to-school decisions for students. Brain Gauge’s metrics are measurements of real brain function. Specific tasks designed to test subject’s response to illusory stimuli have demonstrated that subjects with concussion actually outperform their non-concussed measures. So, not only is Brain Gauge a biologically based measure, but it’s a measure that can’t be faked by understanding the system or “not trying.” A recent article in Military Medicine explored the differences between subjects with and witout concussions.
Adults with autism exhibit inhibitory defcits that are often manifested in behavioral excesses, such as repetitive behaviors, and/or sensory hyper-responsiveness. If such behaviors are the result of a generalized defciency in inhibitory neurotransmission, then it stands to reason that defcits involving localized cortical-cortical interactions (such as in sensory discrimination tasks) could be detected and quantifed.
Previous studies in our labratory demonstrated that we could objectively and reliably obtain cortical metrics - or measures of cortical information processing - via non-invasive multi-site skin stimulation. Sensory percepts evoked by simultaneously delivered stimuli revealed signifcant differences between people with autism and typically developing subjects.
A recent study using corticalmetrics technology found "significant differences in tactile sensitivity between children with ASD and TDC on a number of vibrotactile measures, which may reflect impairments in specific inhibition-related cortical processing in autism...". The authors concluded that "children with autism have possibly reduced inhibitory drive in specific mechanisms as measured with a battery of vibrotactile tasks. The battery is suitable for pediatric populations and acquired in 30 – 40 min..."
Effects of Substance Abuse
While specific cortical regions may be associated with the impulsion and/or motivational factors leading to alcohol use and abuse, alcohol consumption induces a systemic effect on the entire CNS which impacts both cortical and subcortical regions.
In a recent paper featured in Brain Research, corticalmetrics technology was used to measure brain function in a group of college-aged undergoing the use of alcohol. The authors found "the adaptation metrics in this study, although they primarily targeted interactions within somatosensory cortex, are good indicators of systemic cortical alterations. Neural mechanisms involved in the process of adaptation are suspected to be impacted in alcoholism, or with significant alcohol consumption, because chronic exposure to ethanol has been shown to affect GABAergic neurotransmission as well as NMDA receptor densities."
Migraines & Chronic Pain
Headache medicine has few quantifiable biological markers for diagnosis. Screening is primarily dependent on subjective reports of pain and impact of pain on mood, which are assessed at diagnosis and throughout the duration of treatment but are difficult to standardize among various clinical populations. Patients with prolonged migraines often underreport the severity of their symptoms, explaining that they have high pain tolerances or have become accustomed to their headaches. Others may exaggerate, or catstrophize, pain symptoms due to anxiety, depression, or other issues related to secondary pain.
There is a need for an objective, quantitative biological measurement of headache pain severity in order to track improvements or deteriorations in headache pain or chronification over time. Such quantitaive metrics could significantly improve studies of underlying mechanisms, as these objective measures could be used in phenotyping in genetic studies and for assessing impacts of treatments.
In a recent paper published in Brain Research, corticalmetrics technology was used to assess and outline differences between those with migraines and those without. The study found there "were no significant differences found between observations obtained from migrainuers and healthy control subjects on reaction time and tactile detection threshold tasks, and this strongly suggests that peripheral neuropathy does not appear to be a manifestation of migraine." The results from the Temporal Order Judgement task (seen below) led the authors to hypothesize that the "results suggest deficits in frontostriatal cortical function as well as dysfunction in functional connectivity among cortical ensembles in migraineurs." Furthermore, the migraineurs performance on the Amplitude Discrimination Task led the authors to conclude the "results of this study are more consistent with previous research analyzing the balance between excitatory and inhibitory neurotransmission showing that migraineurs show a reduced adaptation metric, which is associated with short term desensitization or habituation, in comparison to healthy control subjects.See more pulications on chronic pain
Brain Gauge and corticalmetrics technology is ideally designed for meauring the impact of pharmacological manipulation. The multi-paramaetric approach provides an objective measure of cognitive function in a number of different important cerebral pathways.
A recent paper in BMC Neuroscience found that "the DXM drug administration had no effect on the subjects' performance on a standard amplitude discrimination task, but it significantly reduced the impact of adaptation on amplitude discrimination"
While it is well known that skin physiology - and consequently sensitivity to peripheral stimuli – degrades with age, what is less appreciated is that centrally mediated mechanisms allow for maintenance of the same degree of functionality in processing these peripheral inputs and interacting with the external environment.
The metrics we collect across the age spectrum could be broadly defined in one of two categories: those that are perphially based and those that are predominatly centrally mediated.
Results obtained from a recent Frontiers in Aging Neuroscience article demonstrated that the peripherally mediated measures, such as threshold detection, were significantly increased by increasing age. This is not suprising, as most of these measures are primarily realted to skin physiology, and it is well established that that sensory thresholds do increase with age. Centrally mediated measures, such as those that rely mechanistically on cortical information processing properties such as lateral inhibition and/or adaptation, however, did not change with age.See more pulications on Aging & Degenerative disorders