People with fragile X have difficulty in sorting out and screening all the messages that come through their senses. They are extremely hypersensitive to their environment. The problems they have in sorting sensory information are called ‘sensory integration deficits’.

These characteristics can increase learning and behavioural problems, as all sensations are received in an extreme form. They may have a negative response to situations that seem normal to others. Such situations include reactions to unfamiliar or strong smells, refusing to wear tight clothing, or clothing made of a rough fabric and being extra sensitive to bright or flashing lights. They are often disturbed in areas of high ambient noise, such as shopping centres and other crowded locations.

People with fragile X may not be able to communicate what is upsetting them. It is important for carers to know about this sensory integration problem. This response to sensory overstimulation has been called ‘sensory defensiveness’. Individual programs, usually involving commonsense ways of organising and reducing environmental stimulation, can be planned to lessen the reaction. For instance, noise which is sensed as too loud, lighting which seems too bright and hypersensitivity to certain types of clothing can all be changed.

Occupational therapy with a sensory integration focus can lessen a person’s sensory defensiveness.