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What is Sensory Perception?

Sensory Perception is the process of handling external signals, input to our senses. Relevant information is recorded while noise and irrelevant data are ignored. This is a three stage process:

1. Input Registration

Usually performed at the sensory organs: eyes, ears, etc. Each sensory organ specializes in a different kind of input. In some cases, as in the ear, signals are spread over a wider spectrum in order to facilitate further processing.


2. Basic processing

After registration, before any direct cognitive involvement. Basic processing includes:

  • Filtering of constant noise and fixed frequency noise

  • Attention Focus – Raising sensitivity for selected input portions

  • Comparison to pre-defined patterns, pre-determined before birth or ‘downloaded’ by the cognitive system

  • Sensory Integration – Information received from all senses are often combined at the basic processing step


3. Cognition

The integrated input from all senses is passed both directly and through the brainstem to brain regions specializing in handling the input (e.g. visual cortex, auditory cortex).  Understanding the meaning of the input is a cognitive process and one of its outcomes is the preparation of patterns used in the ‘basic processing’ step.

What is the difference between sensory perception and sensory sensitivity?

Sensory perception is the term used to describe all activities dealing with perceiving or ‘making sense’ of the sensory input (e.g. filtering, focusing, pattern recognition, etc.). Sensitivity is the ability to handle weak signals and to separate signals that are in close proximity to each other.

What does SensPD measure?

SensPD measures the basic processing step (Step 1.2 of sensory perception definition). Basic processing is key to our ability to ‘make sense’ of sensory input.  Most mammals do not have the human cognitive capabilities, but all of them have basic processing skills. SensPD measures the performance of basic processing. It is known that most people with autism have signal processing issues. On the other hand, no difficulties have been found in people with autism at the sensory registration or cognitive steps.

How does basic processing work?

Audio signals are registered in the brain moving through the eardrum, the tiny ossicles and the Cochlea (The Inner Ear). Inside the Cochlea the inner hair cells convert the mechanical audio signal to a neural/electric signal that is transmitted to the brain.

Inside the Cochlea there are outer hair cells which perform a very important part in handling the input signal. As opposed to the passive inner hair cells, the outer hair cells generate sounds both spontaneously and under the brainstem control that are called Oto-Acoustic Emissions (OAE).  OAE can be recorded by placing a microphone in the ear canal, and is commonly used to diagnose inner ear problems.  OAE recording devices are in common use in every hospital and audiology clinic.  The brainstem controlled OAE is in essence the basic processing step. This mechanism is needed for processing complex signals such as speech.

Does the noise that is generated by the outer hair cells disturb the brain’s signal processing?

By no means.  In the natural world all input signals are accompanied with noise, and as a result, animals at all levels of evolution have learned to cope with it. In the case of mammals, controlled noise generated by the outer hair cells assists in input processing.

What exactly is SensPD’s measurement?

SensPD records the response to a calibrated complex signal (the stimulus) and compares it to a normal response. The result of this comparison is SensPD’s measurement. This measurement of the processing performance serves as a Bio-Marker.

What is the difference between SensPD’s measurement and other OAE measurements?

  • The type of stimulus: SensPD allows for a long complex stimulus which requires a long capture time. Standard OAE measurement uses short stimuli which is too short for Brainstem intervention (minimum 5-6 milliseconds).

  • SensPD measures a wider range of frequencies including speech frequencies.

Therefore, SensPD’s procedure can functionally augment existing instruments.

Why is SensPD’s diagnosis applicable for newborns?

  • The OAE response mechanism which is measured by SensPD develops during the third trimester of pregnancy. This is the reason why newborn OAE measurements is the norm in developed countries.

  • Other direct measurements of brainstem related activities using instruments such as ABR and fMRI have shown differences with children at a high risk for autism at the age of a few months.

Why are earphones with active noise cancelling not used by SensPD?

The active noise cancelling process involves creating sounds that we have no control over. We might consider using this technology in the future after we better understand how it works.

Is it possible that autism develops at a later stage, even at age 2 or 3?

This possibility cannot be negated since, as of now, we do not have an objective way to diagnose autism. There are many researchers that believe that this is true in about a third of the cases.

What are the implications for SensPD diagnosis? Maybe we will diagnose only two thirds of the cases. A repeat of the diagnostic procedure may be needed at a later age.

How do we know that the measurement is specific to autism?

SensPD’s technology measures the performance of the Basic Processing step. There may be other disabilities associated with sensory processing issues. Early diagnosis will also serve these populations

Are there other methods to diagnose autism at an early age?

The common practice for autism diagnosis is the observation of behaviors according to a schedule established by the American Psychiatric Association (APA) and listed in their Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).  It is commonly accepted that the behaviors listed in the manual only manifest themselves around the age of two. This assumption has been challenged and here are some examples:

  • Prof. Ami Klin, measured eye tracking of three-month-old babies and found differences in the results of babies with high risk for autism.

  • Liron Rozenkrantz, found differences between the way infants with autism and typically developing infants responded to a foul smell.

  • Prof. Michael Davidovich, monitored several behavior markers around the age of 9 months and was able to find correlations.


All of these techniques are examples of statistical findings. They do not offer a neurological model that can explain the mechanism behind the behavioral differences.

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