The normal defensive response to any unexpected or unfamiliar sensory input is the primitive, aversive response action of the lower brain stem to an interpreted need for protection. This response triggers the sympathetic nervous system to initiate an autonomic (automatic/involuntary) "fright, fight, or flight" protective response.  Sensory Processing Disorders create a neurological hypersensitivity, or a neurological inability to integrate (remember & recognize) sensory input; resulting in an imbalance between inhibitory and stimulating forces within the nervous system.  When all sensory input is interpreted as unfamiliar or unexpected, the brain can never recognize it as enjoyable, relaxing, or rewarding; it remains frightening, disorganizing and overwhelming.  Below are just a few of the sensory seeking and sensory avoiding symptoms Alex demonstrated as a young child:  

AUDITORY:

• Very easily distracted by noise
• Needing numerous repetitions in numerous modalities to process auditory information
• Unable to comprehend or repeat multi-step auditory directions
• Repeating every word he hears instead of waiting for the entire thought or sentence to be presented
• Grinding teeth or humming in busy or noisy environments
• Covering ears around loud noises or in anticipation or expectation of noise
• Easily distracted by subtle background noises (fluorescent lights, fans, etc)
• Pulling at ears (without no ear infection)
• Complaining of buzzing or ringing noises in ears
• Hyper-sensitivity to high-pitched noises
• Seeking or making strange noises
• Speaking with a voice volume that is too high or too low
• Unable to conceptualize a task, sequence task and execute task (praxis)
• Vocalizing frustration or despair through exaggerated “survival language”(‘I’ll never do it’… ‘I’ll never learn’… ‘I died’…  while falling to the ground or pretending to “die”)

MOTOR COORDINATION:

• Unable to recognize the amount of force needed to manipulate objects:  repeatedly breaking pencil leads when writing, slamming instead of shutting doors, etc
• Unable to coordinate bilateral activities:  tying, skipping, etc
• Exhibiting right-left hand or foot preference confusion
• Avoiding mid-line crossing
• Displaying exaggerated visual motor tics
• Displaying a need to complete a task as quickly as possible (not thinking act through)
• Displaying a need to complete a task perfectly (erasing all written work for a minor flaw)
• Displaying need to rush through transitions
• Hyperventilating & panic attacks (poor respiratory exchange with tight chest muscles, resulting in increased CO2, decreased O2 and increased stress response)
• Displaying primitive reflex responses (exaggerated startle response)
• Seeking fast motion in preferred plane of movement: rotational, vertical, horizontal, inverted or angular.

TACTILE:

• Adverse reaction (primitive response: fight or flight, panic) to light touch 
• Highly sensitive to soaps, detergents
• Highly sensitive to tags and seams in clothing
• Messy dresser – shirts on backward, shorts twisted, socks on upside down
• Can only tolerate baggy, loose fitting clothing made of soft and/or smooth (brushed cotton) fabric
• Difficulty tolerating the manipulation of certain touch textures (art projects, etc)
• Avoiding extended touch (gives “1/2” hugs:  only with one arm & very brief contact)
• Unable to recognize personal space of other people
• Over reactive to others in his personal space
• Avoiding busy places for possibility of jostling or bumping
• Avoiding messy or gritty activities
• Avoiding being touched at all
• Walking on toes to avoid sensory input from bottom of feet
• Highly sensitive to extreme temperatures
• Unable to regulate body temperature

VISUAL:

• Seeking peripheral stimulation activities, patterns, etc
• Drawn to certain colors
• Very drawn to television, computer screens
• Hyper-focusing on visual patterns, etc
• Blinking at bright lights or appears sensitive to sunlight
• Preferring dim or darker lighting
• Squinting when doing puzzles or other highly visual tasks
• Easily distracted by bright or neon visual input
• Unable to make or maintain eye contact
• Rubbing eyes often
• Pulling at eyelashes

VESTIBULAR BALANCE:

• Seeking constant motion (moving, fidgeting, etc)
• Jumping or hopping instead of walking
• Spinning himself or objects around 
• Seeking suspended balance
• Running in circles or figure 8 patterns
• Seeking or avoiding swinging activities
• Unable to balance on bicycle
• Difficulty walking down inclines (ramps)
• Difficulty walking up or down uneven surfaces (hills, driveways)

GRAVITATIONAL INSECURITY:

• Avoiding heights, elevators, and escalators
• Avoiding lifting feet off of the ground
• Avoiding swings or playground equipment
• Avoiding having head tipped backward
• Avoiding the feeling of falling or doing forward rolls
• Hesitates walking up or down stairs
• Unable to jump into pool water

ORAL MOTOR:

• Seeking very sour or tart foods
• Seeking crunchy textures
• Constantly touching or pressing non-food objects to lips or cheeks
• Oblivious to food on or around lips/face
• Avoiding certain food textures (mushy)
• Unable to tolerate extreme temperatures of food or drink (better with cold)
• Making mouth or throat noises:  clicking, humming, ‘growling’,
• Unable to roll ‘r’s or make ‘purring’ sounds
• Salivating excessively (swallow or clear throat often)
• Exaggerated movements or noises with mouth, lips, cheeks, and throat
• Chewing or biting nails or cuticles

PROPRIOCEPTIVE BALANCE:

• Seeking crashing or heavy falling activities
• Seeking rough and tumble play
• Seeking activities that provide heavy work input (hanging, pushing, pulling)
• Seeking deep pressure to joints (flap hands, crack knuckles, press fingers or hands together, etc.)
• Hyper-extending or hyper-flexing torso or limbs
• Jumping or stomping feet heavily
• Pounding or slapping hands or fists or seeking weight on hands
• Purposefully bumping or crashing into everything.
• Unable to judge distance or height to clear or manipulate objects
• Difficulty with projected action sequencing:  poor response time, moving wrong part of body to accomplish task
• Unable to judge strength or force of grasp to carry or manipulate objects (drops everything, tears paper with pencil when writing)