Current literature reveals that methods for quantifying motor syndromes in Cerebral Palsied children are desirable for improved management of the condition.

Four devices for quantifying motor dysfunction in children with Cerebral Palsy are discussed. Motor functions quantified by these devices are passive resistance to motion of the forearm and leg, postural balance, and gait.

The first device measures forearm resistive forces during passive displacement. The force and displacement values are integrated to calculate work. Thirteen normal children and 45 children with Cerebral Palsy were studied. Fifteen of the Cerebral Palsied children were evaluated before and after cerebellar implant. The post-operative evaluation was conducted 6 to 10 days following surgery -with the cerebellar stimulator turned on. These children were not on drug regimens other than those administered pre-operatively, and were not given strong analgesics or tranquilizers during the test periods. A marked decrease in work was observed in this group. Minimal changes in work values were observed in the second group of Cerebral Palsied children evaluated at least 6 months following implant, first with the stimulator off for 4 8 hours and then on for 1 hour (30 subjects tested). Mean pre and post stimulation work values for this group were lower than the mean pre-operative work values of the group studied before implant. Comparison of the two groups is questionable though, because the second study was conducted in a less controlled environment in which patients were easily distracted. Many subjects had also travelled long distances;​ were fatigued;​ and were generally unable to cooperate and fully relax. A 2-linkage mechanical model of the forearm is developed to demonstrate that forearm inertia has a negligible effect upon the measured work values.

The second device measures leg resistive forces as the foot is displaced with the subject seated. Force and displacement values are integrated to calculate work. Tests were conducted on 6 normal and 38 Cerebral Palsied children. Eleven of the Cerebral Palsied children were evaluated before and after cerebellar implant. The post-operative evaluation was conducted 6 to 10 days following surgery with the cerebellar stimulator turned on. These children were not on drug regimens other than those administered pre-operatively, and were not given strong analgesics or tranquilizers during the test periods. A marked decrease in work was observed in this group. Minimal changes in work values were observed in the second group of Cerebral Palsied children evaluated at least 6 months after implant, first with the stimulator off for 4 8 hours and then on for 1 hour (27 subjects tested). Mean pre and post stimulation work values for this group were lower than the mean pre-operative work values of the group studied before implant. Comparison of the two groups is questionable though, because the second group was studied in a less controlled environment in which patients were easily distracted. Many subjects had also travelled long distances;​ were fatigued;​ and were generally unable to cooperate and fully relax. The design of the leg device is such that inertia due to gravitational forces significantly affects the measured work values. A 4-linkage mechanical model is developed to quantify these effects for each subject tested. The measured work values are normalized for inertial effects through the computational procedure.

The third device measrues body center of pressure location. It consists of a square aluminum platform which is corner supported by force transducers. Tabular parameters measured by this system are:​ sway frequency, mean and maximu m sway amplitude, root-mean-square sway amplitude, and path length. Three dimensional plots of radial sway amplitude;​ direction and frequency;​ and center of pressure position are provided. Tests of 5 normal and 5 ambulatory Cerebral Palsied children were conducted. Distinct differences were observed in both groups tested when comparing eyes open and eyes closed sway parameters. The same was true in a comparison of the normal to Cerebral Palsied group, with eyes open and closed. The effect of subject inertia upon the measurements is demonstrated with an inverted pendulum model. Finite element analysis of a family of square, corner supported balance platforms is conducted to determine the locus of load points which produce zero force in at least one support. All loads interior to this locus produce compression in all supports and this region is called the kern of the section. Loads placed outside of the kern produce tension in at least one support. It is shown that balance platforms utilizing unidirectional force transducers may give erroneous results if the subject stands outside the kern. Sources of error associated with the application of signal analysis techniques for quantifying sway frequency are discussed. An alternative approach is developed using peak-trough detection and digital filtering.

The fourth device measures triaxial hip joint motion and foot placement sequence. Electrogoniometers provide angular information. Four switches per foot give placement and temporal information. A pulse-width-modulation unit worn by the subject is used to compress output data into a single channel of information which is relayed via cable to a decoder. This system reduces the number of cables normally used to convey multi-channel goniometric information. Tabular parameters measured by the system are:​ foot placement sequence, stance time, stride time, swing time, cadence, maximum and minimum angles of rotation, and total ranges of angular motion. Angular parameters are computed for the three planes of rotational motion (sagittal, coronal and transverse). Analog records of angular motion and foot placement sequence are provided for each test. Three dimensional plots of each angle and the foot placement sequence for repetitive tests are also provided. Tests of 5 normal children and 5 ambulatory Cerebral Palsied children were conducted. Varying degrees of gait differences between both extremities and slight variations in gait from the same extremity were noted in both groups. A greater amount of gait symmetry was seen in the normal group. Greater sagittal flexion was noted in the Cerebral Palsied group, though sagittal range of motion values tended to vary by limb. Coronal range of motion was greater in the Cerebral Palsied group. No significant differences in transverse range of motion were seen. Differences in foot placement sequence between limbs was noted in both groups, as were differences between groups.