Upper extremity amputees who used a prosthesis had poorer touch pressure sensibility in the residual limb compared with upper extremity amputees who did not use a prosthesis, according to recent study results.

“In adults with acquired upper extremity amputations, it is still unclear whether sensibility changes after amputation, and if so, whether this change influences prosthetic use. Furthermore, it is unknown to what extent sensibility influences functioning of upper extremity amputees with or without prostheses. Such knowledge may be relevant to the rehabilitation of these patients,” the researchers wrote. “In unilateral transtibial amputees, diminished touch pressure and kinesthesia were noted in the unaffected legs of patients with vascular as well as traumatic amputations. Such a change in sensibility on the unaffected side may also be present in upper extremity amputees. Thus, the inclusion of healthy controls seems to be the preferential method for examining sensibility.”

Sensibility testing

Researchers identified 30 patients with an acquired upper extremity amputation, at least 1 year after amputation and 30 age-, gender- and hand dominance-matched controls through databases from two participating hospitals and the website of the Dutch National Patient Association for Amputees.

Willemijn van Gils

Touch pressure sensibility was tested using Semmes-Weinstein monofilaments. Stereognosis was also detected using the Shape and Texture Identification test, as well as kinesthesia. Researchers assessed daily functioning using the Upper Extremity Functional Status Module of the Orthotics and Prosthetics Users’ Survey. Amputees were asked to complete a short questionnaire concerning their medical history, education level, amputation level and cause, use of prosthesis at the time of the study and for which activity the prosthesis was used. Controls received a separate questionnaire concerning their medical history and education level.

Study results showed the residual limb tended to be less sensitive to touch pressure compared with corresponding points on the unaffected arm. Patients who used a prosthesis exhibited significantly poorer touch pressure sensibility in the residual limb vs. those who did not use a prosthesis. Overall, when compared with the arm and hand of amputees, controls had significantly better touch pressure sensibility of the arm and hand.

Researchers found most patients were unable to complete the Shape and Texture Identification test using their residual limbs.

Except for one patient, all patients and controls achieved a maximum score on the kinesthesia test and no difference was found in functional status between the prosthetic users and nonusers, according to study results.

“In the future, it would be interesting to investigate whether training after a major upper extremity amputation could improve sensibility and whether such training influences functioning with or without a prosthesis,” Willemijn van Gils, MD, of the department of rehabilitation medicine at the Center for Rehabilitation, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands, told O&P Business News. “Further research is necessary to determine if this is true and what kind of training this should be.”

Surprising results

The researchers noted two unexpected results. First, the touch pressure sensibility of the residual limb of patients who did not use a prosthesis was better compared with the sensibility of the prosthesis users. Researchers believe this result might suggest patients who experience better limb sensibility choose not to use a prosthesis, or frequent skin stimulation could improve sensibility after amputation.

They also surmised decreased stereognosis of the amputees’ index fingers compared with the controls’ index fingers may be caused by greater callus formation on the patients’ fingers. — by Casey Murphy