Aging Clin Exp Res, Vol. 20, No. 4 1 Key words: Aging, cervical joint position sense, cervicocephalic relocation test to neutral head position, proprioception. Correspondence: Nicolas Vuillerme, PhD, Laboratoire TIMC-IMAG, UMR UJF CNRS 5525, Faculté de Médecine, 38706 La Tronche cédex, France. E-mail: nicolas.vuillerme@imag.fr Received April 18, 2007; accepted in revised form August 17, 2007. Cervical joint position sense is impaired in older adults Aging Clinical and Experimental Research Nicolas Vuillerme, Nicolas Pinsault, and Benjamin Bouvier Laboratoire TIMC-IMAG, UMR UJF CNRS 5525, La Tronche, France ABSTRACT. Background and aims: Although the role of afferent input from cervical muscles on the con- trol of posture and locomotion is recognised, it is sur- prising that there is an absence of data reporting whether joint position sense at the cervical level is impaired in older healthy adults. The present experi- ment was designed to address this issue. Methods: Eighteen young (mean age= 23 yrs) and 18 older healthy adults (mean age= 68 yrs) were asked to per- form the cervicocephalic relocation test (CRT) to the neutral head position (NHP), that is, to relocate the head on the trunk, as accurately as possible, after ac- tive cervical rotation to the left and right sides. Ten tri- als were performed for each rotation. Absolute and variable errors were used to assess cervical joint repo- sitioning accuracy and consistency, respectively. Re- sults: Less accurate and less consistent repositioning performances were observed in older adults than in young adults, as indicated by increased absolute and variable errors, respectively. Conclusions: The present findings show that cervical joint position sense, as- sessed through the CRT to the NHP, is impaired in old- er adults. (Aging Clin Exp Res 2008; 20: ###-###) © 2008, Editrice Kurtis repositioning errors made by young healthy adults were compared with those made by older healthy adults, when performing the cervicocephalic relocation test (CRT) to the neutral head position (NHP) (15-17). METHODS Participants Eighteen young adults (age= 23±2 yrs; body weight= 61±15 kg; height= 171±9 cm; mean±SD) and 18 older adults (age= 68±7 yrs; body weight= 74±11 kg; height= 169±9 cm; mean±SD) voluntarily participated in the experiment. They gave their informed consent to the experimental procedure as required by the Helsinki dec- laration (1964) and the local Ethics Committee. Sub- jects were healthy, without any history of cervical pain, whiplash injury, headache, trauma, operation on the cervical spine, or neurological disorders. Procedures The experimental procedure of this test (16), which has recently demonstrated excellent test-retest reliability (17), is illustrated in Figure 1. Blindfolded subjects were seated on a chair with a backrest at a distance of 3 meters from a white wall, with their head in a neutral position. They were asked to re- locate their head on the trunk to the NHP with maximum precision, without any instructions regarding speed, after active head movement performed in the horizontal plane within comfortable limits. Subjects had a laser pointer at- tached on the head and a handheld button to switch it on to materialize their NHP before (Point O; Fig. 1, upper panel) and after (Point G; Fig. 1, lower panel) head re- location. Ten trials were executed after one right head rotation and ten after one left head rotation. Right and left head ro- tations were randomized over subjects. No feedback was given to them about their actual performance. The video recorded during the session contained all laser impacts characterizing head positions before and af- INTRODUCTION Age-related deterioration in the proprioceptive sys- tem is well documented (e.g., 1 for a review). Previous studies have reported that older adults exhibit marked joint position sense impairment, measured at the ankle (2, 3), knee (4-8), trunk (9), elbow (10) and finger (11) levels, as a result of normal aging. At this point, however, al- though the role of afferent input from cervical muscles on the control of posture and locomotion is recognised (e.g., 12-14), it is surprising that there is an absence of da- ta reporting whether joint position sense at the cervical level is impaired in older healthy adults. The present ex- periment was designed to address this issue, and head Ready for press Return by Fax to n° +39 049 8211818 Signature ...................................................................