STUDY DESIGN: This is a single-center retrospective study. OBJECTIVES: The objective of this study was to study the clinical symptoms and electrophysiological features of C6-7 @entity602 . SETTING: This study was conducted at the Department of Orthopedic surgery, Yamaguchi University Graduate school of medicine, Japan. METHODS: A total of 20 @entity1 with cervical @entity1745 were determined by spinal cord-evoked potentials or a single level of obvious magnetic resonance imaging (MRI)-documented cervical @entity1745 . Neurological examinations included manual muscle testing and investigation of deep tendon reflex, including Hoffmann sign, and of sensory disturbance areas. Motor-evoked potentials (MEPs), compound muscle action potentials (CMAPs) and F-wave were recorded from bilateral abductor digit minim and abductor halluces muscles. Central motor conduction time was calculated as follows: MEPs latency-(CMAPs latency+F latency-1)/2 (ms). RESULTS: Eighteen @entity1 (90%) had negative Hoffmann sign. Eight @entity1 (40%) had no sensory disturbance in the upper limbs and 8 @entity1 (40%) had no @entity425 in the upper limbs. We determined that @entity1 had cervical @entity602 when their central motor conduction time measured in abductor digit minim was longer than 6.76   ms (+2 s.d.). Using this definition, the sensitivity for @entity602 was 42.8%. CONCLUSION: @entity1 with C6-7 @entity602 may lack clinical symptoms in their hands and central motor conduction time measured in abductor digit minim tended to be less prolonged, and it only showed symptoms in their lower limbs as gait disturbance. Surgeons should bear in mind the possibility of disorders of caudal C6-7 when they encounter @entity1 with no or few symptoms in their hands and with @entity425 .Spinal Cord advance online publication, 17 November 2015; doi:10.1038/sc.2015.203.

Characteristics of C6-7 XXXX : assessment of clinical symptoms and electrophysiological findings.

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients'] @entity602 :: ('MESH:D013118', 'Disease') :: ['myelopathy'] @entity1745 :: ('MESH:D013117', 'Disease') :: ['spinal cord compression', 'compressive myelopathy'] @entity425 :: ('MESH:D018908', 'Disease') :: ['leg weakness or numbness', 'muscle weakness']
@entity602 :: (MESH:D013118,Disease) :: ['myelopathy']
