Intrathecal baclofen normalizes motor strategy for squatting in familial spastic paraplegia: a case study

We aimed to assess whether intrathecal baclofen could alter the motor strat egy for squatting of a patient with pure familial spastic paraplegia. Befor e baclofen injection and two, four and six hours after it, the patient was evaluated as follows: self-report of walking stiffness and movement initiat ion; muscle tone with the Ashworth scale; and kinematic and electromyograph ic analysis of the squatting movement using the opto-electronic ELITE syste m. The patient's subjective improvement and decrease in muscle tone were dr amatic after baclofen injection. Kinematic analysis of squatting showed gra dual improvement. Before the injection, the movement was performed with los s of trunk verticality, backward shift of the hip, multiphasic ascending ph ase of the knee angular velocity and dynamic ankle stiffening. After baclof en injection, the movement was made with vertical translation of body segme nts and monophasic ascending phase of the knee angular velocity. The effect was maximal six hours after the injection. Electromyographic activities sh owed a non-specific co-contraction pattern before the injection, and a reci procal pattern two hours after it. Moreover, a physiological anticipatory d eactivation of the hamstring muscles appeared two hours after the injection . In this study of a single patient with familial spastic paraplegia, intra thecal baclofen has facilitated the emergence of normal, supraspinally dete rmined movement patterns. (C) 2000 Editions scientifiques et medicales Else vier SAS.