The most common cause of the latter is orthostatic hypotension (also called postural hypotension). Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia, rigidity, and postural instability. Lesions of these tracts result in profound ataxia and postural instability. Pulmonary physiotherapy and postural drainage are also important. Other symptoms include postural instability and retching. The rectus abdominis is an important postural muscle. Generally damage to the vestibulospinal system results in ataxia and postural instability. CTTH can also benefit from combined therapy from stress therapy, exercises and postural correction. It is found mostly in teenagers and presents a significantly worse deformity than postural kyphosis. Akinetic seizures can present with sudden loss of postural tone without associated tonic-clonic movements. Typical treatments include combinations of head and eye movements, postural changes, and walking exercises. This load shift is believed to help in compensating for postural imbalance. Bracing has been known to provide cutaneous afferent feedback in maintaining postural control. The iliacus and psoas major perform different actions when postural changes occur. A study investigated the effect of mental rotation on postural stability.