Sensory Mismatch and the persistence of symptoms in upper neck problems

The following information is likely to be relevant to all individuals with a chronic neck pain problem or with any history of ADHD, or a number of other chronic problems such as migraine or fibromyalgia. It will not provide a complete solution to any of these problems but is likely to help management of them very much.

Our ability to perceive the world accurately is dependent upon the capacity to accurately integrate the different sensory data received by our brain.

In particular the three senses of vision, balance (vestibular apparatus) and somatosensory proprioceptive information need to be matched accurately in real time.

Somatosensory information is derived from stretch receptors in each muscle, but a very large proportion of this information comes from muscles in the upper neck.

It is now proven that tension and fatigue in muscles causes distortion of the somatosensory information coming from that muscle such that it no longer accurately reports body position.

This leads to a series of downstream effects in the nervous system that include impaired balance, impaired co-ordination, impaired eye muscle co-ordination leading to loss of depth perception and difficulty with eye tracking that makes reading difficult, error prone and stress provoking.

The balance impairments also lead to an increase in muscle tension as the brain responds by puling the head down harder on the neck to minimise the risk of

The major problem that we face is that the fatigued muscles are usually not obvious except by direct palpation– if you do not poke them you will not know they are causing trouble.

Equally, the balance problems caused by neck muscle tension are subtle and usually long standing, and not obvious except to direct questioning. Equally an affected individual might have mastered a sport and have good balance in the context of that sport but not elsewhere.

These unrecognised balance problems though do generate a chronic stress response and a chronic sense of anxiety in most affected individuals. Being unaware of the true cause of the anxiety , most individuals attribute it to situational issues such as the perceived behaviour of those around them

Since the start of 2014 my practice has focussed on management of ADHD and chronic pain syndromes, and all my patients have been initially assessed with questionnaires that look specifically for issues with neck and back pain, headaches, balance, coordination, reading ability and sensory integration. There is also a careful assessment for a history of head injury and upper cervical birth trauma. This has been followed with specific physical examination that reviews posture, postural stability, balance, cerebellar function, and eye tracking, and more recently with detailed questionnaires usually used by behavioural optometrists.

The conclusion of my observations is as yet unpublished but several common themes arise.

Virtually all ADHD patients have issues with balance, co-ordination and eye tracking and usually neck or back pain. Most ADHD adults are dissociated from their bodies and score very poorly on assessment of interoceptive ability when I introduce them to body canning meditation. Most also have immense difficulty in mirroring me when I teach them basic exercises to help their posture. This reflects an impairment in visuospatial awareness- which often drives much of the disorganisation and many of the incidents of losing personal effects so common in ADHD. Virtually all have poor posture- dominated by a functional kyphoscoliosis and postural instability. Most have abnormally high muscle tone in superficial muscle groups. Equally the majority of adults presenting to my practice with ADHD have noted a deterioration in the context of changed circumstances with require that they spend more time sitting reading (ie promotion, or taking on extra study).

These observations fit well with the observations made by Stray et al in 2009 in their study of co-ordination problems in a cohort of Norwegian children diagnosed with ADHD.

Ref: The Motor Function Neurological Assessment (MFNU) as an indicator of motor function problems in boys with ADHD

Stray LL et al: Behavioral and Brain Functions 2009, 5:22 doi:10.1186/1744-9081-5-22

While causation of ADHD is complex and multifactorial I am formally proposing that in the overwhelming majority of ADHD patients the final common pathway generating and maintaining ADHD symptoms involves a positive feedback loop between neck muscle tension causing distorted somatosensory perception, and leading to sensory mismatches between somatosensory, visual and vestibular inputs. The nature of this problem is that it then creates such postural instability and such negative impact on vestibular function and eye coordination that the actual sensory mismatch is in a state of continuous change. This instability is an essential part of the equation as it prevents any recovery through passive learning.

The downstream effects include (but are not limited to) impaired balance, a chronic stress response, asymmetric cerebellar activity (and downstream asymmetric cerebral hemispheric activity), and impaired eye co-ordination leading to a loss of stereopsis, and making reading difficult, stressful, and likely to be experienced as “boring”. A thorough neurological examination will reveal clear physical signs that correlate with all of these problems.

I am also formally proposing that this feedback loop is involved in maintaining other difficult to treat syndromes like anxiety, whiplash, migraine, chronic fatigue and chronic pain syndromes (and probably most syndromes labelled as psychosomatic).

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