The Sensory System
No one has a perfectly functioning sensory system. We all have sensory preferences and even sensory needs, each unique to how our central nervous system perceives and processes sensory information. Think about your sensory system being like electrical wiring. When there is a kink in a wire, it may cause lights to flicker. Sometimes we get a kink in our central nervous system, and that leads to mixed messages in our sensory system. Many times, we may not know what is causing that kink or how to stop our own internal lights from flickering. When sensory processing is disorderly, the brain cannot do its important job of organizing sensory messages.
Sensory Processing Challenges
Sensory processing challenges can affect how a person moves and learns. These challenges can also affect how a person behaves; completes tasks at home, school, or work; and interacts with others. When we have sensory processing challenges, we may experience touch, taste, sound, smell, movement, and other sensations differently. Some may feel sensations more intensely, others feel them less so, and some just do not get sensory information "right" - up may feel like down or a penny may feel the same as a button. These sensory responses can lead to challenging behaviors (Will et al., 2019).
Sensory processing problems are relatively common among individuals with Down syndrome, and certain difficulties are reported more often than others. However, it is important to remember that each person is unique, and it should never be assumed that one person with Down syndrome will have the same sensory problems as another. Additionally, even though sensory deficits are often associated with autism spectrum disorder (ASD), individuals can have sensory deficits without also having an additional diagnosis of ASD.
Individuals with Down syndrome may have sensory challenges related to proprioceptive input. Proprioceptive input is sensory input to the muscles and joints. People with Down syndrome tend to have low muscle tone, which can affect how they interpret sensory input coming in through their muscles and joints (Bruni, 2016). Frequently they require more proprioceptive input into their muscles and joints in order to help regulate their bodies. This also makes it challenging for people with Down syndrome to regulate the amount of force they generate with their muscles; they often do something too hard (apply too much pressure to an object so it breaks) or not hard enough (apply insufficient pressure and have a hard time holding on to an object).
Sensory processing deficits may make daily tasks like bathing, dressing, and eating a challenge. We often see and hear that patients do not tolerate lotion on their skin, despite it being dry. Some individuals do not like water touching their face, which affects bathing and hygiene. People with Down syndrome may not like to wear socks, shoes, or other pieces of clothing because of the way the clothing feels. Transitioning from one season's clothing to the next may also be a challenge.
Individuals with Down syndrome may also have sensory-related eating problems. For example, they are often reported to be picky eaters. Some may stuff their mouth full when eating. This may be due to proprioceptive deficits. In order for a person to chew, he/she must feel the food in their mouth, and they might only have this sensation if they stuff their mouth full to the cheeks. This is not a safe eating habit. Other feeding issues that are reported include difficulties feeling thirst or satiation (fullness). This is related to the interoceptive system, one of the eight sensory systems. For more information on the eight sensory systems, please refer to the article from the STAR Institute at this link .
Individuals with Down syndrome may experience sensory-related hearing problems. Many people with Down syndrome have hearing loss or wax buildup in their ear canals, which can muffle sounds. They may get overwhelmed by loud or unexpected sounds yet prefer their music at a loud volume. Compounding these hearing problems, they often have difficulties with auditory processing. Thus, they often perform best with visual cues or instructions verbalized in simple ways and repeated often. Depth perception is also a challenge for many individuals with Down syndrome and can make it difficult for them to go up and down stairs or maneuver on uneven surfaces.
Addressing Sensory Challenges
When individuals with Down syndrome have sensory difficulties, those problems should be addressed in order to help them live each day feeling regulated. Sensory processing deficits are not something that are outgrown; they grow and change with us. Treatment is highly individualized and will help a person function more smoothly. An occupational therapist (OT) can provide direct therapy in an outpatient setting or direct or consultative therapy in a school setting. A therapist will create a sensory diet, which is a planned and scheduled activity program designed to meet a person's specific sensory needs. Some trial and error may be needed to determine the "best" sensory activities for each person.
Building and implementing a sensory diet should be more like choosing from a menu rather than following a recipe (Johnson, 2016). One main aim of a sensory diet is to prevent sensory and emotional overload by satisfying the nervous system's sensory needs. For instance, if a sensory diet activity is done before another activity, it can help a person move through the transition or prepare for a change in routine more easily (Johnson, 2016). However, it can also be used as a recovery technique if the person does become overwhelmed. A sensory diet can be implemented at home and in the community (e.g. school, day program, or work). One key feature to remember, especially when considering behavior plans, is that sensory strategies should never be removed as punishment or given as a reward. If a person has a sensory diet, it is because it is needed for optimal performance, and the person's body begins to rely on it.
Activities as part of a sensory diet should be offered periodically throughout the day. Sensory breaks can be short in length, often only for a few minutes. Sensory input should not be provided all day long. For instance, a weighted vest will often lose its impact after approximately 10 to 15 minutes. Think about what happens when you put on jewelry. You may notice the necklace or ring initially but, at some point, you usually forget you are wearing it. It is the same with sensory input. There is a point when the body gets used to the sensation and tunes it out, making it effective no longer.
In summary, everyone has sensory processing differences. When these differences impair a person's ability to function day to day, we may want to consider therapy options to help. When people have a regulated sensory system, they are better able to pay attention, follow directions, and perform at an optimal level. This is true for people both with and without Down syndrome.
Additional resources on sensory processing and Down syndrome can be found here.
Bruni, M. (2016). Fine Motor Skills in Children with Down Syndrome. 3rd ed. Bethesda, MD: Woodbine House.
Johnson, D. (2016). Differentiating sensory from behavior [presentation]. Retrieved from https://summit-education.com/course/CSENDJ.1/differentiating-sensory-from-behavior#/onlinevideo/6-ceus .
Will, E., Daunhauer, L., Fidler, D., Lee, N., Rosenberg, C., & Hepburn, S. (2019). Sensory processing and maladaptive behavior: Profiles within the Down syndrome phenotype. Physical and Occupational Therapy in Pediatrics, 39(5), 461-476. https://doi.org/10.1080/01942638.2019.1575320