1. Motor symptoms of ADHD

Author: Ulrich Brennecke
Review: Dipl.-Psych. Waldemar Zdero

Hyperactivity is a common symptom of ADHD, but not all people with ADHD are hyperactive.

In children, hyperactivity manifests itself in constant fidgeting, standing up or running around.
In adults, hyperactivity decreases, but restlessness of movement and certain behaviors such as finger drumming, foot tapping or nail biting may still occur. Motor hyperactivity may decrease over time, while inner restlessness may remain or become more visible. It is debated whether inner restlessness is a separate symptom and whether it is related to drive problems.

Men with and without ADHD show higher provoked hyperactivity than women in the Quantified Behavioral Test. Both men and women with SDHD have a doubled basal and a tripled provoked hyperactivity compared to non-affected persons.¹

Conclusion: These results suggest that females with ADHD suffer from hyperactivity to the same extent as males, challenging the assumption of gender-dependent expression of hyperactivity. This could lead to more accurate and timely diagnoses and reduce the burden and comorbidities associated with ADHD in females.

Hyperactivity and inner restlessness are also symptoms of stress. Stress hormones such as CRH can cause restlessness of movement. Gross motor problems such as clumsiness and coordination problems are common in ADHD-HI and ADHD-C. Fine motor problems such as poor handwriting and difficulties with fine motor tasks can also occur. It is unclear whether fine motor problems can be improved by ADHD medication.

The data from the ADxS.org symptom test showed that motor hyperactivity decreased with age, while restlessness and attention problems persisted.

While it has been recognized that attention problems in ADHD are primarily a motivational problem (lack of self-motivability), as intrinsically interesting topics can arouse attention while intrinsically non-interesting topics cause attention problems, it is largely unknown that this is also true for motor restlessness. A Time-lapse video showing a person with ADHD watching an intrinsically interesting and an intrinsically uninteresting videoillustrates that hyperactivity problems are also caused by motivational factors.

• 1.1. Hyperactivity
  • 1.1.1. Motor hyperactivity as an ADHD symptom
  • 1.1.2. Manifestations of motor hyperactivity
  • 1.1.3. Age-related decline in motor hyperactivity
  • 1.1.4. Hyperactivity as a stress symptom
• 1.2. Gross motor problems with ADHD
• 1.3. Fine motor problems with ADHD

1.1. Hyperactivity¶

Motor hyperactivity is a very common symptom of ADHD. However, hyperactivity is not a mandatory symptom of ADHD. There are people with ADHD who suffer greatly from their symptoms, who were/are neither hypermotoric as children nor full of inner restlessness as adults.

1.1.1. Motor hyperactivity as an ADHD symptom¶

Motor overactivity is a characteristic of ADHD-HI and ADHD-C. Hyperactivity is less pronounced in the ADHD-I subtype (predominant attention problems).²
Hyperactivity often subsides in adolescence. The specialist literature describes that hyperactivity in adults usually turns into a form of inner restlessness. This will need to be discussed.

The fidgeting and constant movement could be understood as an internal correction of vigilance (internal basic tension) and low dopamine levels. Movement increases the dopamine level.³⁴ People with ADHD who are forced to sit still are (even) more likely to give incorrect answers than when they are allowed to move.³ Similarly, sports before school (to act out motor restlessness) increases learning success.³
Children with ADHD showed a shorter reaction time in the Stroop test and improved self-efficacy with simultaneous exercise (cycling). In children without ADHD, the result was unchanged.⁵ The authors concluded that hyperactivity in ADHD may be a compensatory mechanism to upregulate hypoarousal in the PFC to support executive functions and self-efficacy.

1.1.2. Manifestations of motor hyperactivity¶

• for small children:
  • Extended childish defiant phase
  • Possibly with excessive, veritable, real tantrums
• for children:
  • Constant fidgeting with hands and feet or sliding around on the chair (DSM IV/5)
  • Is often present in class and other situations where sitting is expected (DSM IV/5)
  • Frequently runs around or climbs excessively in situations where this is inappropriate (in adolescents or adults this may be limited to a subjective feeling of restlessness) (DSM IV/5)
  • Often has difficulty playing quietly or engaging quietly in leisure activities (DSM IV/5)
  • Is often “on the move” or often acts as if he/she is “driven” (DSM IV/5)
  • Often talks excessively (DSM IV/5; categorized as impulsivity in ICD-10). Speech diarrhea can also be observed in some adults
• for adults:
  • Hyperactivity (external/physical) decreases by up to 60 % in adults⁶
  • Physical restlessness in adults, possibly only to a lesser extent
    • Foot tapping with high frequency (or impulse to do so, which is deliberately suppressed)⁷
    • Finger drumming (or impulse to do so, which is consciously suppressed)⁷
    • Chew nails⁸
    • Biting lips
    • Knot legs / wrap around chair leg to limit movement⁸

1.1.3. Age-related decline in motor hyperactivity¶

The data from the ADxS.org symptom test show the following changes in the age groups:

Age group	Motor hyperactivity	Inner restlessness	Attention problems
5- 9 years (n = 9)	0.70	0.80	0.75
10 - 14 years (n = 15)	0.72	0.68	0.83
15 - 19 years (n = 48)	0.45	0.62	0.81
20 - 29 years (n = 373)	0.49	0.70	0.81
30 - 39 years (n = 492)	0.49	0.74	0.83
40 - 49 years (n = 301)	0.46	0.74	0.78
50 - 59 years (n = 158)	0.46	0.72	0.80
60 - 75 years (n = 32)	0.42	0.74	0.72
Men (n = 630)	0.52	0.73	0.81
Women (n = 823)	0.45	0.72	0.80

As at June 2020. The values given reflect the severity of the symptoms relative to each other.
Limitations of informative value:

• There are few data sets with test persons under 20 years of age and far too few data sets with test persons under 10 years of age for a reliable statement.
• There was no separation of ADHD-I and ADHD-HI, so the (random) ratio of ADHD-I to ADHD-HI may skew the data for small group sizes.
• Only the data sets in which the symptom test found indications of existing ADHD were evaluated.
• This is a non-validated online self-test (screening).

The data can be discussed in relation to the thesis that attention problems in children up to the age of 15 are not yet fully developed and that motor hyperactivity diminishes in adulthood. However, they indicate that hyperactivity does not transform into inner restlessness, but that inner restlessness also exists in children and merely recedes to a lesser extent than hyperactivity. After the regression of motor hyperactivity, inner restlessness merely appears to become more visible.

Inner restlessness could be described as the “little brother” of hyperactivity.

1.1.4. Hyperactivity as a stress symptom¶

Hyperactivity and fidgeting are known to be typical symptoms of severe stress, as is the fact that thoughts concentrate on the stressor (circling thoughts, rumination).
Stress symptoms from the hyperactivity spectrum are:

• Restlessness¹⁰¹¹
  Inner restlessness is a typical symptom of the approaching final state of burnout.¹²
• Restlessness¹³¹⁴
• Restlessness of movement¹⁵

The stress hormone CRH, which is released by the hypothalamus in the first increment of the HPA axis, directly mediates an urge to move. Increased locomotor activity is a direct effect of the stress hormone CRH.^1617181511

Symptoms that are directly mediated by stress hormones themselves can nevertheless also be ADHD-specific symptoms. Chronic stress such as ADHD mediate their symptoms through a lack of dopamine and noradrenaline in the brain.

1.2. Gross motor problems with ADHD¶

Gross motor skill problems are a symptom of ADHD.^19202122 They are already present in young children and correlate with sleep problems in children. More than half of people with ADHD are said to have gross and fine motor problems.^23242526
Gross motor and fine motor disorders should be considered separately from motor hyperactivity.

Forms of appearance:

• Clumsiness
  • Frequent bumping/sticking
• Many accidents (clumsiness meets hectic pace)
  • Frequent injuries (esp. ADHD-HI)
  • Bruises
• Coordination problems (dyscoordination)
  • E.g. learning to ride a bike at the age of 6
  • E.g. difficulty maintaining balance or standing on one leg²⁷
• Difficulties with force dosage

Initial data from the ADxS.org online symptom test (as of October 2018) suggests that gross motor problems are far more common in ADHD-HI with hyperactivity than in the ADHD-I subtype. Studies prove the connection between gross motor problems and hyperactivity/impulsivity.²⁸

It is possible that motor problems in the form of deficits in interpersonal (automatic) (motor) synchronization contribute to the development of social problems. Interpersonal synchronization requires good motor control and is also important in the development of mother-child relationships²⁹
Interpersonal synchronization plays an important role in the acquisition of social cognitive skills in development.³⁰³¹ In ADHD, the extent of interpersonal synchronization between mother and child correlates with the level of functioning of preschool children with ADHD.³²
Another hypothesis assumes a connection between impaired eye control (gaze control and gaze saccades (eye movements)) and ADHD symptoms such as attention problems and impulsivity.³³

1.3. Fine motor problems with ADHD¶

Fine motor problems are a symptom of ADHD.²¹³⁴³⁵ More than half of people with ADHD are said to have gross and fine motor problems.²⁵
Fine motor and gross motor disorders should be considered separately from motor hyperactivity.

Forms of appearance:

• Handwriting problems³⁶
  • Scrawly handwriting³⁷
  • Disproportionately increasing with dictation under time pressure³⁸
• Children find it difficult to color pictures neatly³⁸
• Precision mechanics are difficult (e.g. smooth cuts with scissors, inserting small screws)

Fine motor problems should

• be more common with ADHD-I²⁵
• be about equally common in ADHD-HI and ADHD-I³⁹

According to a review, between 28% and 67% of people with ADHD also show improvements in their fine motor skills as a result of ADHD medication.²⁵ Our impression is that this is rather rarer.