injury are muscle paralysis and loss of sensation. The distinction is made between paralysis involving both the arms and the legs (quadriplegia) and that of the legs only (paraplegia). Quadriplegia results from injury to one of the eight cervical segments or neck region of the spinal cord. Paraplegia results when the injury is confined to the thoracic, lumbar, or sacral regions of the cord. In general, the higher the injury is to the cord, the more severe the impairment will be. An estimated one-half of all SCIs result in quadriplegia (Stover and Fine, 1986). More than 95 percent of paraplegic individuals achieve independence in specific self-care activities and mobility in a wheelchair (Young et al., 1982). Quadriplegic individuals often require frequent physical assistance in performing personal care tasks such as feeding, dressing, and bathing but may still be independent in the performance of communicative and cognitive activities such as operating a computer.

SCIs are also characterized according to the extent of neurologic injury. Complete injuries, or plegia, result in complete loss of sensation or motor control. In contrast, people with incomplete lesions, or paresis, may retain some sensation and motor power, with the degree of impairment depending on the extent of the lesion. Overall, approximately one-half of all SCIs are complete lesions (Stover and Fine, 1986).

Studies of patients treated at Regional SCI Centers have reported 5-year employment rates ranging from about 14 percent for quadriplegics with complete lesions to 33 percent for paraplegics with incomplete lesions (Stover and Fine, 1986). Again, estimates are influenced by the length of follow-up and the preinjury characteristics of the patient population. A recent study (Whiteneck et al., 1989) reported that 63 percent of a select group of high-level quadriplegic individuals on respirators had survived 9 years and were leading fulfilling lives.

Older adolescents and young adults are at highest risk of SCI. Compared with females, males are at three to four times the risk of sustaining SCI. Very little is known about the correlation between SCI injury and race or ethnicity. The few studies that have examined this relationship report conflicting results (Kraus, 1985).

Motor vehicle crashes of all types constitute the major cause of SCI in the United States, accounting for between 30 percent and 60 percent of all SCIs. Falls constitute the second leading cause, accounting for an additional 20 percent to 30 percent of all cases. Acts of violence (primarily involving firearms) and sports or recreational activity also contribute significantly to the incidence of SCI, each accounting for an estimated 5 percent to 20 percent of all SCIs. Diving is the major cause of sports-related SCI, being implicated in two-thirds of all sports-related SCI reported by the Model Spinal Cord Injury Systems Program. Football injuries also contribute greatly to SCI in the United States (Stover and Fine, 1986).

The extent of injury is related to cause. Nearly one-third of all falls and



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