Pain and lack of balance are the most frequent symptoms which bring adult patients to the clinic.
Specific learning difficulties and attention deficit are the most frequent symptoms in children.
The proprioception system is a global system, and the manifestations of a disfunction of this system can be located in any area of the body. No clinical case will present every possible sign and symptom at one time, but a combination of signs and symptoms, with one, possibly two, dominant symptoms which will lead the patient to seek medical help. For example, patient A’s dominant symptom could be chronic or acute pain; patient B’s could be lack of balance; and patient C could present cognitive impairment as their dominant symptom. Patients A, B and C, however, are diagnosed using the same proprioception dysfunction diagnostics protocol; and they respond to the same proprioception dysfunction treatment protocol.
Even within the same main type of signs and symptoms, different areas of the body can be differently affected. For example, regarding:
1. Chronic or acute pain: a patient's main complaint could range from headaches or migraines; or neck pain, upper spine pain, or lower spine pain, including cruralgia and sciatalgia.
2. Lack of balance: a patient may present as the main symptom vertigo, dizziness, frequent falls, unsteadiness, mal de débarquement, or nausea/sickness.
3. Cognitive impairments: a patient may present as the main symptom a low attention span, poor spatial orientation, memory impairment, or difficulties in interpreting information including visual and auditory information.
The ophthalmic signs and symptoms are of great diversity and complexity. The main optic pathways terminate in the occipital cortex; the secondary optic pathways, which are of particular interest to PDS, project to the superior colliculus and further to the mesencephalon. The oculogyric centres responsible for the main ocular movements are multiple and located in the occipital and frontal lobes, and these two structures in turn are far from the nuclei of the oculomotor muscles. It is well known that injuries in the parietal and temporal lobes can affect image perception. These structures are also connected with each other, and their complexity is very high.
Visual scotomas are evidenced through computerised campimetry (Visual Field Test), with areas of relative and absolute scotomas located para-centrally and in the periphery. The distribution of these scotomas does not correspond to any neurological condition, and it can be incorrectly interpreted as low-pressure glaucoma;
monocular diplopia/poliopia can occur with one image of the target object centred in the fovea and another image or other images centred in an anomalous fixation point or several anomalous fixation points. An error of the proprioceptive information in relation to the exact position of the ocular globe relative to the target leads to a discrepancy between the objective and the subjective gaze object;
binocular diplopia/poliopia due to reduced capacity of near fusion and loss of near ocular convergence;
convergence insufficiency with symptoms of astenopia;
oculomotor discoordination with the patient presenting inability to coordinate the eyes in most gaze positions, with symptoms of diplopia and incomitant ocular deviation often associated with nystagmiform movements (this situation is rare);
near exotropia with exodeviation at near with associated diplopia, with no deviation and with single vision at distance; frontal lobe migraine related to convergence insufficiency;
metatopsia with, for example, patients reporting seeing walls, floors, ceilings and pictures curved or distorted; sensation of ocular globe retraction;
ophthalmic migraine due to visual misperception. This can include micropsia, visual scotomas and photopsis; errors of spatial localisation presented as straight lines being perceived as curved, a picture hanging straight being perceived as crooked; a vertical wall being perceived as leaning; and whilst reading, lines in a text being perceived as jumping; errors of egocentric localisation can also be present. These errors vary with the direction of gaze and include the inaccurate perception of the distance between the own body and surrounding objects, which appears to be shorter than what it is in reality, and other people may appear to be taller in relation to the than what they really are.
To understand the relevance of proprioception for egocentric spacial location it is important to consider two questions: how does the brain of an observer know where surrounding objects are in relation to the observer?; and how does the brain know where the eyes are in relation to the rest of the body? The exact location of an object in relation to an observer is given by the perception of the position of the eyes in relation to the rest of the observer’s body, and by the perception of the position of the eyes in relation to the object. It is not the retina that informs the brain about the exact location of the objects that surround the observer, in relation to the observer.
The image of the object is projected, independently of its location in relation to the observer, to a specific visual area in the occipital lobe. This visual cortical area is the only area in the brain to receive this specific information about the object; the brain knows where the eyes are because of the perception of the difference in tonus between the oculomotor muscles. When looking straight ahead, there is a tonic equivalence between the lateral rectus and the internal rectus in each eye. When looking sideways, one of these muscles has higher tonus than the other, as one is contracted and the other is relaxed.
It is the perception of higher or lower tonus that indicates to the brain the location of the target object. By changing the muscular tonus of oculomotor muscles, the egocentric spatial localisation can be changed. The correct perception of the relative tonicity of the oculomotor muscles is crucial - if there is a dysfunction of proprioception, this perception is altered.
The Eye-Hand Test was developed by Orlando Alves da Silva to assess egocentric spatial location by evaluating the accuracy of reach of the observer towards an object. An error of spatial localisation allows us to conclude that in PDS there is an error of the perception of the tonicity of the oculomotor muscles. Active Prisms normalise the error of localisation.
Disturbances of locating the body in space are manifested by difficulties with left and right; frequent falls due to difficulties in locating the body in relation to the ground, and the several body segments in movement between themselves i.e., tripping over ones feet; spatial disorientation; problems with parking due to difficulty in estimating automatically the distance between own vehicle, the parking space and other parked vehicles; difficulty in estimating automatically and with precision the distance between the hand and an object to grab; frequent twisted ankles due to errors in estimation of the position of the foot in relation to the ground.
In PDS, the symptoms associated with lack of balance are believed to be caused by a dysfunction of the perception of the body i.e. of proprioception, and not to a dysfunction of the labyrinth. Patients with lack of balance report dizziness; frequent falls; vertigo (even when lying down with the eyes closed); feeling of inebriation; sensation that the body is oscillating; unsteadiness; instability when stepping; mal de débarquement; or nausea/sickness. Note, that in orthostatic position, the human body presents normal physiologic oscillations that are undetected by individuals, and do not have any associated symptoms.
Cardiovascular signs in PDS include decrease in the normal range of blood pressure due to higher diastolic measurements (for example, 120 systolic and 90 diastolic); fainting; irregular and asymmetric blood flow to the face as measured by facial thermography; pallor; cold and sweaty hands; and Reynaud syndrome.
A number of cognitive dysfunctions can be found in individuals with PDS that can impair the process of learning, irrespective of intelligence levels.
These include attention deficit; concentration deficit; dyslexia, with difficulties in reading and/or difficulties in understanding text even when the text appears to be read well; hyperactivity, with the need for constant movements even when sitting down, and hypoactivity alternating with periods of hyperactivity, with students falling asleep in class or lectures; movements with lack of precision and poor coordination; dysgraphia, presenting irregular handwriting, without following line markings and spacing; dysorthographia, making mistakes when copying and during dictation.
A pervasive and long-term feeling of exhaustion without there being a cause, is also a symptom of PDS. Fatigue CFS/ME can be explained because the tonic fibre component of muscles throughout the body remains contracted for long periods of time, without the normal periods of relaxation - note that the normal physiology of the tonic fibre component of muscles is such that there is a constant tonic oscillation of contraction and relaxation.
Gastrointestinal signs include paradoxical reflux, more frequently in the orthostatic position. This is distinct from the classic gastroesophageal reflux due to insufficiency of the cardia, which typically takes place when lying down; feeling nauseous; alternation between constipation and diarrhoea.
Hearing, taste, smell and touch/pressure
The hearing signs may lead to learning delays in the class or lecture, and to misunderstandings at work as patients cannot follow instructions in real time.
They include perceptual deafness characterised by inability to perceive sounds despite normal results to audiometry testing; delay in auditory perception, due to a lag time needed to process the audio information; tinnitus; and hyperacusis. Alterations of taste and smell, including partial or total loss, or conversely exacerbation of taste and smell can also occur. In PDS light touch/pressure can be perceived as pain, with patients frequently referring to feeling pain when others touch their hair, or feeling pain in the soles of their feet when getting up.