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1. ISIS Institut de Recherche sur le Handicap Gilles KEMOUN (1,2), Pierre CARETTE (1), Nicole FLOIRAT (1), Eric WATELAIN (3)(1) Physical Medicine and Rehabilitation Department, University Hospital of Poitiers, France(2) Laboratoire des Adaptations Physiologiques aux Activités Physiques - EA 3813, University of Poitiers, France(3) Laboratoire d'Automatique de Mécanique et d'informatique Industrielles et Humaines - UMR CNRS 8530, University of Valenciennes, France Cognitive and postural effects of the trace of an unresolved traumatic emotional episode INTRODUCTION : In normal subjects, the postural regulation system leads to a forward shift of the center of pressure (CP) in close-eyed (CY) as opposed to open-eyed (OY) conditions [1]. Connections between thymo-cognitive factors and postural disorders have likewise been established. For example, it has been shown that anxiety may have direct effects on vestibulary functionning through some central interconnections between the balance central system and the vegetative nervous system [2]. It has also been proposed that emotion, anxiety, procession of vestibulary information and vegetative control may share common networks in the brain. The goal of our study is to show that people having undergone a traumatical emotional episode, even a very old one, have posturographic changes. These modifications correspond to a backward shift in the center of pressure in CY conditions. MATERIALS : We used a Dune® 3 receptor stabilometric platform giving a two dimensional analysis sway of the center of pressure (COP), placed in a examination cabin closed on three sides (front, right and left side), eliminating extraneous visual stimuli (horizontal and vertical) allowing to obtain a standardization of visual input (Palus and al 1984). Cabin depth : 2m ; width : 1.5m ; height : 2.4m. The platform is on a low-based analyser 60cm X 40cm. A removable mark is installed behind the subject’s feet assuring reproducible positioning including a foot angle opening at 30°. Visual target lit at 2000 lux a focal point 90cm in front of the platform. The examination is performed in a stable acoustical environment, thus avoiding distraction of the Subject examined (Gurfinkel and al, 1972). Measurements : Recordings lasted 51.2 seconds on a 5Hz sampling frequency. Each recording was repeated twice.The average of the two recordings was used. The platform was calibrated before each recording. Weekly checks were done to rule out center of pressure (CP) displacement. The « eyes open barefoot » measurement was used as the reference point. Each person received an explanation about the platform and procedure methods before recording. The subject was placed barefoot on the platform, his back to the posturologist and facing the lighted target. His position on the platform was standardized with a removable foot mark. The recording started immediatly after its removal. Measurement conditions were identical for all the subjects. METHODS : A prospective study on 379 consecutive patients having consulted for chronic pain of the locomotor apparatus. All of them have benefited from a force platform trial. This was followed by a semi-directed interview by a practicioner uninformed from the posturographic data. This was meant to perceive the patient’s psycho-affective history, particularly the existence of a traumatic emotional episode. The qualitative variables used were: - the presence or absence of forward shift in CY conditions as opposed to OY conditions in the antero posterior axis - the presence or absence of an old traumatic emotional episode RESULTS : 271 subjects have a forward shift in CY conditions and none have had a traumatic emotional episode. 108 subjects have backward shifts and among them 100 present the trace of a commonly old traumatic emotional episode. Chi² test is significant (p<0.001). The different types of unresolved emotional traumatisms observed were: - Severe accidents (road and traffic accidents, shipwrecks, accidents at home, sports injuries), - Physical aggression. (mistreatment, harassment, torture, rape or attempted rape, incest, robbery, menaces at gunpoint, injuries with firearms or bladed weapons) - War, fires, natural disasters (floods, avalanches, earthquakes), sudden death of a close friend or family member - Large-scale surgical interventions. DISCUSSION : The subjects affected by persistence of the unconscious trace of an emotionally trying episode have their CP shifted backwards under close-eyed conditions in comparison to CP positioning under open-eyed conditions. This postural behavior may be placed in relation with phobic avoidance. The elimination of visual information under close-eyed conditions favors vestibular pathways known to be interconnected with the limbic system and the tonsil, that is to say with thymo-cognitive information. [3]. This posturographic sign would appear able to indicate the nociceptive trace of an unresolved traumatic emotional episode along with the need for detection and treatment. These results are coherent with regard to those of other studies establishing the link between postural balance and psychological status. [4]. Recent morphological studies likewise corroborate the existence of neural networks common to postural regulation and cognitive and emotional functioning. [5]. These interactions should be taken into account when interpreting symptoms. Moreover, this reciprocal link may represent a therapeutic trail to be pursued. CONCLUSION : The different studies featuring psychological assessment and stabilometric measurement of subjects suffering from anxiety disorders of the obsessive-compulsive type lend credence to the hypothesized existence of thymo-cognitive input that may exert continuous and significant influence on postural control. Such action on postural control is a measurable and quantifiable datum obtained by means of psychometric scales in conjunction with measurements taken on a force platform. The influence of the psyche and, more specifically, of these types of disorder and dysfunction should be taken into account in future studies that might be carried out by means of analysis of orthostatic posture. It will be just as important to envision the integration of thymo-cognitive information – along with visual, vestibular and somato-sensory information - in postural regulation. References : 1- Tarantola J et al (1997). Human stance stability improves with the repetition of the task: effect of foot position and visual condition. Neurosci Lett. 228:75-8. 2- Bolmont B et al (2002). Mood states and anxiety influence abilities to maintain balance control in healthy human subjects. Neurosci Lett. 329:96-100. 3- Perna G et al (2001). Panic disorder: the role of the balance system. Journal of Psychiatric Research. 35: 279–286 4- Balaban CD, Thayer JF (2001). Neurological bases for balance-anxiety links. J Anxiety Disord. 15:53-79. 5- Atmaca M et al (2007). Volumetric MRI study of key brain regions implicated in obsessive-compulsive disorder. ProgNeuropsychopharmacol Biol Psychiatry. 31:46-52 Standardization of visual input cabin Visual target Platform Removable foot mark