This can affect how an individual processes sensory information such as sounds, sights, textures, tastes, and smells, as well as their balance and movement experiences.

Difficulty processing sensory information often co-exists with conditions like Autism, ADHD, Developmental Delay, Intellectual Disability, Anxiety, or mood disorders.  However, individuals without any of these conditions can also have Sensory Processing Disorder.

Behavioural and emotional responses to SPD can be very strong, particularly in response to sensory overload, anxiety, or fear around certain sensory experiences. These responses can significantly impact daily functioning, social interactions, and learning, particularly where the individual withdraws or avoids activities involving (unpleasant) sensory stimuli. For children, it can affect their participation in school, play, and social activities. Adults may find it challenging to navigate workplaces or public spaces.

The most common type of Sensory Processing Disorder is Sensory Modulation Disorder (SMD). SMD occurs when an individual has difficulties regulating their responses to sensory input.

Individuals with SMD may be overly-responsive (hypersensitive) or under-responsive (hyposensitive), or a third possible category is that they may be sensory-seeking.

Sensory Over-Responsivity (Hypersensitivity)

Individuals with Sensory Over-Responsivity often have intense reactions to sensory stimuli, which may span several senses or be limited to a few. Sensory Over-Responsivity stands out as the most identified category of SMD, and examples of responses, by sense, are as follows:

• Auditory: Strong reactions to loud noises, such as covering ears or experiencing distress in noisy environments.
• Visual: Discomfort in bright lights or environments with a lot of visual stimuli, leading to squinting or aversion to certain colours and patterns.
• Tactile: Avoidance of certain textures, such as clothing tags, specific fabrics, or materials like sand and finger paint. They may also react strongly to unexpected touches.
• Gustatory: Extreme picky eating habits, avoiding foods with certain textures or temperatures.
• Olfactory: Strong reactions to specific smells, often leading to avoidance of certain places or activities because of those odours.
• Vestibular: Fear of heights, reluctance to use playground equipment like swings and slides, and avoidance of activities that require balance.
• Proprioceptive: Discomfort with certain postures or body positions and difficulty with tasks requiring fine motor skills, such as writing or buttoning clothes.

Sensory Under-Responsivity (Hyposensitivity)

Sensory Under-Responsivity involves reduced or delayed reactions to sensory stimuli. Examples by sense are as follows:

• Auditory: individuals may have a diminished response to sounds, including not responding to one's name or being unaware of loud noises and background sounds.

• Visual: individuals might struggle to notice details or changes in their environment and lack response to visual cues.
• Tactile: can present as unawareness of dirt on hands or face or not noticing or responding to injuries that would typically cause pain.
• Gustatory: may prefer very spicy, salty, or sour foods or have limited interest in food
• Olfactory: there may be a minimal response to strong or unpleasant odours
• Vestibular: demonstrated by constant movement, such as rocking or spinning, with a high tolerance for movements that typically cause dizziness in others
• Proprioceptive: clumsiness or awkward movements and a desire for activities providing strong proprioceptive input, such as jumping or crashing into things.

Sensory Seeking

The third category of SMD is individuals who have Sensory Seeking behaviours, which are characterised by an intense craving for sensory experiences. The signs can be:

• Auditory: making loud noises or talking constantly, enjoying noisy environments.
• Visual: staring at spinning objects or lights and enjoying fast-moving visual stimuli.
• Tactile: constantly touching objects or people and seeking out different textures.
• Gustatory: mouth or chew on non-food items and crave strong flavours.
• Olfactory: sniff objects or people and enjoy strong or unusual smells.
• Vestibular: engage in constant movement, such as jumping or spinning, and enjoy activities that provide intense movement input.
• Proprioceptive: engage in activities involving heavy work, such as lifting or pushing, and enjoy deep-pressure activities like tight hugs.

If multiple signs of Sensory Modulation Disorder are experienced, and interfere with daily life, it may be beneficial to seek evaluation and support from an Occupational Therapist. You may be recommended to undertake a Sensory Assessment. Sensory Assessments help to determine an individual’s sensory preferences and provide recommendations and a tailored intervention plan.

Interventions could include a personalised sensory diet - which is a list of activities to complete to satisfy the craving for sensory input. Or recommendations to use support items (e.g. weighted items) or strategies (e.g. movement or quiet breaks) to support sensory sensitivities or needs. An occupational therapist can also prepare a treatment plan to help an individual do activities they normally avoid because of sensory issues. The end goal is to support learning, engagement, and the best quality of life.