Overall , there are many scales and tests used to assess the balance disorders and disabilities of people with PD .
Postural instability is common in Parkinson ’s disease ( PD ) , often contributing to falls , injuries , and reduced mobility .
In the clinical setting , balance disorder is commonly diagnosed using clinical tests and balance scales , but it is suggested that the most sensitive measurement is the force platform .
The aim of this systematic review was to summarize the methods and various posturographic procedures used to assess the body balance and gait in PD .
Effects of dopamine on postural control in parkinsonian subjects: scaling, set, and tone.
1 . This study investigates the effects of parkinsonism and of dopamine replacement therapy ( levodopa ) on scaling the magnitude of automatic postural responses based on sensory feedback and on predictive central set . Surface reactive torques and electromyographic ( EMG ) activity in response to backward surface translations were compared in patients with parkinsonism ON and OFF levodopa and in elderly control subjects . Correlations between the earliest postural responses [ initial rate of change of torque and integrated EMG ( IEMG ) ] and translation velocity provided a measure of postural magnitude scaling using somatosensory feedback . Correlations of responses with expected translation amplitude provided a measure of scaling dependent on predictive central set because the responses preceded amplitude completion . 2 . Parkinsonian EMG responses in six leg and trunk muscles were not later than in elderly control subjects . In fact , quadriceps antagonist latencies were earlier than normal , result ing in coactivation at the knee not present in control subjects . EMG activation was fragmented , with short burst duration s and high tonic levels that often returned to baseline with multiple bursts . In addition , parkinsonian responses showed smaller-than-normal agonist extensor bursts and larger-than-normal activation in tibialis and rectus femorus antagonist flexors . 3 . Although parkinsonian subjects scaled postural responses to both displacement velocities and amplitudes , their torque response were smaller than those of elderly controls , especially in response to the largest displacement amplitudes . The gain ( slope ) of postural response magnitude scaling to displacement velocity was similar for parkinsonian and control subjects , although parkinsonian subjects had smaller torques . Parkinsonian subjects were also able to use prediction to scale responses to small expected displacement amplitudes , but many patients did not generate the larger plantarflexion torques required at larger displacement amplitudes . Reduced torque at large amplitudes was associated with less agonist gastrocnemius IEMG , increased tibialis antagonist burst responses , and increased tibialis tonic background activity . 4 . Levodopa further reduced the already low magnitude of initial torque and IEMG responses to displacement velocities and amplitudes in parkinsonian patients . The ability to scale postural responses to velocity feedback was not affected by levodopa , but the ability to scale responses to large displacement amplitudes based on central set was worsened by levodopa . Levodopa also significantly reduced the tonic , background levels of EMG , particularly the distal gastrocnemius and tibialis activity . 5 . High baseline muscle tone was apparent in parkinsonian subjects from their high background EMG activity in quiet stance , especially in tibialis and quadriceps , and the slow initial velocity of center of mass falling in response to displacements . By reducing tone , levodopa reduced passive stiffness to perturbations without increasing EMG burst magnitudes , result ing in less resistance to external displacements and thus faster center of body mass ( COM ) displacements . 6 . The biggest postural deficit in parkinsonian subjects was not in response latency , pattern , or reactive or predictive scaling of response magnitude , but in quickly generating an adequate level of postural force . Dopamine improved tonic background postural tone but further weakened automatic postural responses to external displacements . Thus the basal ganglia may participate in postural control by regulating appropriate levels of background postural tone and by enabling adequate force generation for resisting external displacements
Overall , there are many scales and tests used to assess the balance disorders and disabilities of people with PD .
Postural instability is common in Parkinson ’s disease ( PD ) , often contributing to falls , injuries , and reduced mobility .
In the clinical setting , balance disorder is commonly diagnosed using clinical tests and balance scales , but it is suggested that the most sensitive measurement is the force platform .
The aim of this systematic review was to summarize the methods and various posturographic procedures used to assess the body balance and gait in PD .