How It Works
The test works by presenting auditory probes to a person while recording the electrical activity from the brain. The outcome of the test can tell if the subject took part in an activity and the specific nature of planning an activity. The test allows differentiation of a perpetrator or participant from a witness. It c involvement including an also help identify a person from a group who has performed a specific activity.
“B.E.O.S.” refers to a signature extracted from the electrical oscillations of the brain of a person, obtained while presenting probes related to specific events in which the person is suspected to have participated. The signature represents the presence of electrical activation pattern indicating retrieval of Experiential Knowledge of the said participation. The signature is absent while the subject retrieves information, which one could have conceptually (from sources other than participation) acquired.
Neural processing / activation are different during retrieval of knowledge acquired through experience in comparison with retrieval of knowledge acquired through conceptual learning. Retrieval of Experiencing Knowledge may have components of sensory-motor mental imageries representing reality contacts and verifications, though the knowledge derived is only subjectively verified and interpreted.
Extensive research in Neuroscience has shown that the brain activation pattern is significantly different during ‘remembering’ and ‘knowing’. Remembrance is always that of past personal episodes which constitutes the experiences of the individual. On the other hand knowing represents retrieval from the knowledge bank of the brain used for recognition of the entities of world and their conceptualizations.
The technique has immense forensic and medical application as it can extract ‘signature’ related to specific experiences with personal significance, one has gone through in the past and hence one is bound to remember. These experiences may be related to personal participation in activities, which may include planning, discussions, and even strong intentions which served as motives for execution of specific actions. Generally one remembers only those experiences which have personal significance to the self. Emotions, gains, and such personal values attached to the participation render an event personally significant and retrievable.
An important feature of the test is that the subject is not presented with questions and need not answer or provide any response while listening to the probes.
“Neuro Signature System” represents the equipment designed and developed by Axxonet. It records scalp electrical activity from a person using multiple electrodes and the N.S.S. program extracts the signature, if present, when the subject silently listens to the probes. The probes are presented in auditory mode.
The Visual and Auditory Stimulus Programming (V.A.S.P.) system allows recording and compilation of the probe file in different Scenarios, marking events, etc. as well as creating video presentations for priming the subject. The probes are presented in a predefined manner by the V.A.S.P. computer. They are sequentially interlinked and are designed after extensive interviews with the investigating officers and the suspects (subjects). The forensic expert who intends to use the B.E.O.S. profiling, needs extensive training in the neuropsychological principles of probe designing. Special efforts are made to probe the antecedents of the suspect and gather confirmed and non-controversial information of significant experiences in the life of the suspect, which are used as “Control Probes”.
The suspects version of his or her involvement in the crime also forms the basis for designing the probes. These probes help to exonerate the suspects, especially when they refer to alibi for them. The first set of probes presented to a subject is called “Neutral Probes” and the electrical activation elicited by these probes is used for baseline corrections.
The Neuro Signature System carries out extensive analyses of the electrical oscillations for computing both frequency and time domain related changes induced and provoked by the probes. At the end of the automated analyses, the system prints out an interpreted report which tells the nature of involvement, if any, of the subject in the said activities probed by the test. Based on the probes presented, it can indicate if the subject took part in an activity, the specific role played by one, whether related to planning or execution. It can also help identify a person from a group who has performed a specific activity or determine the differential roles of the individuals tested.
The N.S.S. records electrical activity, using 30 cephalic electrodes. Additionally 2 eye movement channels, 2 EMG channels, and 3 autonomic measures are also recorded. The online video of the subject is continuously captured during the test. The probes are printed along with the electrical activity and the auditory form of the probe as heard by the subject is also recorded (which can be played back). The final data file is an encrypted one containing the raw data, audio of the probes, the video of the subject and details of the probes, none of which can be edited or altered.
At the end of the presentation of the probes, an epoch file is automatically generated from the continuous raw data acquired by the system. The original data file and the analysis file contain unfiltered data collected using preset band pass filters used while recording. Online monitoring and analysis of the electrical activity allows determining the preponderance of oscillations from which the system determines if the subject is attentive, whether the subject is engaged in parallel processing (mentally chanting, counting, meditating, etc.), is drowsy, making movements thereby producing electrical artifacts, etc. The probe is presented only when predefined brain electrical oscillations profile is detected.
The N.S.S. program analyses response to each probe in each electrode location using a single trial analysis methods developed by Axxonet. Signal processing is carried out for computing the energy parameters of various oscillation ranges, as well as time domain changes provoked by the probe. The signal processing and associated statistical analysis runs into more than several thousands of independent analyses for each probe. The analyses comprise of topographical distribution of the scalp recorded bioelectrical activity with emphasis on anterior-posterior, left-right hemisphere changes, and other topographically relevant changes.
The probability level set for determining significant changes is 0.001 for all frequency analyses and greater than 2 Standard Deviation for responses compared to mean baseline data levels from each electrode, in the time domain analyses. The N.S.S. program looks for predefined profiles across electrodes to determine primary auditory processing of the probe, its encoding, familiarity of the probe content, and presence of Experiential Knowledge if provoked, by each probe.
Continuous research is in progress at Axxonet for better understanding and refining analysis methods for the detection of the various changes recorded during the presentation of the probes, their display, and their neurocognitive significances.
The N.S.S. program carries out the entire range of analyses and the interpretation of the analyzed results automatically and prepares the Forensic Report of the suspect. The forensic expert has no role to play in the analysis program. The N.S.S. technology allows validation of the technique every time it is used on a subject by using the responses to “Control Probes”. The test can be repeated on the same subject on another occasion for determining the reliability of the findings. The test findings are considered forensically significant, when Experiential Knowledge is consistently present for relevant sequence of events referred by probes. Absence of responses indicating Experiential Knowledge of episodes that really took place in the life of a person may have significant clinical value in diagnosing the brain condition responsible for it.
The test can be used as a powerful investigatory aid. The investigating agency has the duty to be confidential about the outcome revelations of the test, unless the same is otherwise revealed by material evidence and are presented in a court of law.
There are limitations to the test as it cannot be used on individuals who may be emotionally disturbed, or with mental handicap, psychiatric disorders (psychoses, depression, etc.), neurological disorders of the brain, drug, and alcohol dependence.
Results of the Normative Study using B.E.O.S. Profiling are presented in several conferences and published in their proceedings.