In reviews of Dravet syndrome, statements about gait are usually very generalized, along the lines of: ” by the age of 13 years, up to 80% of people with Dravet syndrome walk with a crouch gait”. However, it would be useful to have a more specific, and detailed, description, which is what the current paper presents. The research centers involved have used very sophisticated cameras and other equipment to make extensive and detailed analyses of the stances and walking patterns of children and young adults with Dravet syndrome.
They did find abnormalities of gait in these patients, which seemed to fall into two distinct patterns. The first pattern (35%) was defined as “atypical-crouch”, and displayed substantial knee and hip flexion, along with increased step width. It was called “atypical” because walking lacked rotations of the femur and tibia as seen in standard crouch gait. The second pattern (65%) was defined as “straight”, and did not differ much from those of age-matched controls, except for some increase in hip flexion in the stance, and increased step width. They could find no correlation of either group with age, height, or weight.
It seemed to the researchers that the atypical crouch gait denoted a strategy to stabilize walking, in that the increased step width and the increased flexion of the legs lowered the center of mass, thereby increasing stability. The same strategy could also be the purpose of the wider step width, seen in both groups. In the view of the authors, biomechanical factors, such as flat feet, contribute to the gait disturbances. This suggests certain rehabilitative approaches – for example, foot lever dysfunctions could be corrected with orthotic insoles.