What really makes a child with ADHD different from other children?
A Brazilian research team thinks they’re on the right track to finding out. They found that children with ADHD actually sense things differently than other children, which may lead to the host of behavioural and emotional issues associated with the disorder.
What are senses? Senses are how we interact with the world around us. Signals from sensory organs such as the eyes, ears, nose, tongue, and skin are sent to the brain, where the brain then has to make sense of these signals. Even though our surroundings don’t change, they appear different to everyone based on how each individual’s brain interprets the signals it receives from their sensory organs.
A test has been developed that can tell how a particular child’s brain interprets the sensory information it receives. By comparing the results of this test to other children’s scores, healthcare practitioners can tell if a child’s interpretation differs from “normal,” and if it does they can tell how.
How did kids with ADHD score on this test? Children with ADHD scored significantly lower than normal on most of the sections of the test, which means that the way their brains interpret sensory information is significantly different from most other children. The sections which they scored the lowest on were:
- Movement: Children with ADHD were found to have a high threshold for movement and balance signals. This means that their brains do not recognize the signals that a typically developing child’s brain would recognize because they are not as sensitive. In other words, they need more movement signals than normal in order to feel the same response. This could explain why children with ADHD seem to be constantly moving around – they just don’t feel it as much.
- Auditory Processing: This section relates to hearing. Children with ADHD were found to have either a very high or a very low threshold in this area:
A low threshold in auditory processing means that the child genuinely hears more than other children because their brain pays more attention to things it hears than normal. Children like this are easily distracted by things they hear.
A high threshold in auditory processing means that the child’s brain pays less attention than normal to things it hears. A child like this may not hear things you say to them. They may seem like they don’t pay attention, but it may be because their brain doesn’t register things it hears.
- Emotion: Children with ADHD showed significant impairment in emotional sections of the test, including areas related to self esteem, anxiety, how much frustration they can handle, and how irritable they are. The authors of this study think this may be a result of an inadequate ability to process sensory information. For example, if a child feels overwhelmed by the things they sense every day, they may score lower in these areas.
- Behaviour Disorders: The authors found relationships between scoring low on particular sections of the test and certain behavioural disorders which were pre-diagnosed using the Child Behaviour Check List (CBCL) and the Behavioural Teacher Rating Scale (EACI-P). Please see the chart below for the associations.
- Response Patterns: There are four overarching response patterns to sensory information. This test found that children with ADHD tend to show significant impairment in at least one of these response patterns, although the results differ with each child. The four general ways children with ADHD respond to sensory information are:
- Responding slowly. For example, not remembering information easily.
- Seeking constant stimulation. For example, never sitting still.
- Responding easily to all information. For example, being easily distracted.
- Displaying the need to avoid some senses. For example, being bothered by noises.
What should we take away from this study? This study found that children with ADHD experience their senses significantly differently than typically developing children. It also found that each child with ADHD experiences their senses uniquely. There is a lot of variation within a diagnosis of ADHD, and what works for one child may not work for another. If you have a child with ADHD, it is important that they receive a sensory profile so that you (and everyone interacting with your child, such as healthcare practitioners and teachers) can understand the specific ways that they experience their senses. A sensory profile can reveal where the difficulties lie and can help you understand and make the necessary accommodations to help at school, home or the workplace.
Chart and explanation:
The test items revealed information about 14 categories of sensory processing (letter categories below), which can be grouped into three major groups (numbered groups below):
- Sensory processing
A. Auditory processing
B. Visual processing
C. Vestibular processing
D. Touch processing
E. Multisensory processing
F. Oral processing
2. Sensory modulation
G. Sensory processing related to endurance/tone
H. Modulation related to body position
I. Modulation of movement affecting activity level
J. Modulation of sensory input affecting emotional responses
K. Modulation of visual input affecting emotion and activity level
3. Behaviour and emotional responses
L. Emotional and social responses
M. Behaviour outcomes sensory processing
N. Items indicating threshold for response
From the scores on the categories above, the researchers identified nine factors (large Roman numerals below) and four response patterns (small Roman numerals below) of sensory processing:
I.Sensory seeking
II. Emotionally reactive
III. Low endurance
IV. Oral sensory sensitivity
V. Inattention/distractibility
VI. Poor registration
VII. Sensory sensitivity
VIII. Sedentary
IX. Fine motor/perceptual
i. Low registration
ii. Sensory seeking
iii. Sensory sensitivity
iv. Sensation avoiding
The following is a chart showing the associations made between behavioural disorders and the sections above. The disorders were previously diagnosed using the Child Behaviour Check List (CBCL) or the Behavioural Teacher Rating Scale (EACI-P).
| Behavioural disorder | Sections associated with a low score |
| Child Behaviour Check List | |
| Affective Disorder | A, B, L, N, II, VI |
| Anxiety Disorder | D, L, iii |
| Attention Disorder | C, L |
| Oppositional Defiant Disorder | L, II |
| Conduct Disorder | A, E, L, V |
| Behavioural Teacher Rating Scale | |
| Hyperactivity/conduct problems | D, iv |
| Independent functioning | M, IX |
| Inattention | A, M, N, V, IX, iv |
| Neuroticism/anxiety | N |
| Socialization problems | I (letter), L, N, II, VIII, iv |
Source: Shimizu, V. T., Bueno, O. F. A., Miranda, M. C. (2014). Sensory processing abilities of children with ADHD. Brazilian Journal of Physical Therapy, 18 (4), 343-352.
Written by: Katherine Christ, at Simone Friedman Speech-Language Services
