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Biomedical subjects

R M Johnson

Publications and source records attributed to R M Johnson.

212 records · Page 12Linked to original sources
PubMedDate not supplied

Directional variance in skin movement.

Skin tension is known to affect the amount of movement in normal skin and has been theorized to have a possible influence on burn scars. This study measured the directional variance in skin movement, which is related to this theory. Twenty adult female volunteers had 5 predetermined skin sites tested; these sites were on the ventral surface of the upper extremities (UE), from the shoulder to the wrist. A 1 kg axial traction force was randomly applied to each skin site in both proximal and distal directions. The skin was load-cycled 6 times before movement was measured with the use of a laser beam projection. Analysis was performed for each site, and pooled data was normalized for the entire UE. Distal skin movement was significantly greater than proximal movement at each of the 5 test sites and for the UE as a whole (P < .001). No significant differences were found among like-direction sites. Only subject height and length of UE correlated strongly (r = .88). This study demonstrates a difference in skin movement and discusses how these findings may relate to the theory that skin tension could be involved in burn scar contracture and hypertrophy.

Adult↗
PubMedDate not supplied

Multimodal versus progressive treatment techniques to correct burn scar contractures.

The treatment of burn scar contractures is a major emphasis in the rehabilitation of patients with burn injuries. Many treatment techniques have been used successfully but without a critical investigation of the best practice of care. In this study, we compared the outcomes for pediatric and adult patients treated with a multimodal therapy approach to treatment techniques that are considered to be progressive to determine if differences existed in the techniques. The medical records of 52 patients with documented burn scar contractures were reviewed for patient and rehabilitation treatment parameters. Included were population demographic information and type of treatment intervention used to correct the scar contracture. In particular, the postburn day when the contracture appeared, the percentage of range of motion deficit, the day when definitive treatment that eventually corrected the contracture was begun, and the days required to correct the contracture were noted. With equal range-of-motion deficits identified, the burn scar contractures of patients in the progressive treatment group were corrected in less than half the time of the burn scar contractures of the patients in the multimodal treatment group. This result occurred despite scar contractures that appeared significantly earlier and later initiation of definitive treatment.

Adolescent↗
PubMedDate not supplied

Correction of spinal instability and recovery of neurologic loss following cervical vertebral body replacement. A case report.

While replacement of cervical vertebral bodies may be required when they are compromised by infection, tumor, or injury, or when they impinge on the neural elements, this procedure does not add immediate stability and may cause additional problems. In this case, displacement of a large fibular graft into the spinal canal appeared to cause additional spinal cord and nerve root injury. Despite a long delay, decompression and firmly fitted and wired anterior and posterior grafts seemed to enhance the neurologic recovery and permitted rapid mobilization. The diagnostic value of computerized tomography is also demonstrated.

Adolescent↗
PubMedDate not supplied

The loudness of tinnitus.

Paradoxically, measurements of the loudness of tinnitus indicate that the noise is not a very loud one, yet many persons experiencing it report severe distress. It has been suggested that either loudness has not been measured correctly or that some other factor such as recruitment may be involved. These aspects were investigated, with the following results: (1) the loudness levels obtained for two methods of measuring the loudness of tinnitus differed significantly with the proposed method yielding measures of greater magnitude without exception; (2) recruitment was evidenced for all subjects. On the basis of the results the following conclusions seem justified: (1) the loudness of tinnitus may be more intense than previously reported; (2) the proposed method for measuring the loudness of tinnitus appears to be a more valid measurement than the traditional method.

Adult↗
PubMedDate not supplied

The controversial relationship between loudness discomfort levels and acoustic reflex thresholds.

Controversy presently exists concerning the relationship between loudness discomfort levels (LDL's) and acoustic reflex thresholds (ART's). In this study, LDL's and ART's were obtained for two groups of ten normal-hearing adult subjects and one group of ten adult subjects with bilateral sensorineural hearing losses. The procedure involved obtaining LDL's and ART's under earphones and under sound field conditions for four different acoustic stimuli: pure tones, warble tones, spondaic words, and speech spectrum noise. One group of normal-hearing subjects and the hard-of-hearing group of subjects were given "too loud, uncomfortably loud, or annoyingly loud" LDL instructions while a second group of normal hearing subjects were instructed to respond when a sound "first starts to become uncomfortable." Results indicated that LDL's, irregardless of instructional pattern, were reported at consistently higher sound pressure levels than the ART's, for all groups of subjects. The magnitude of the differences between the LDL's and ART's varied according to LDL instrucitons, type of test stimulus, hearing sensitivity of the subjects (normal hearing or hard-of-hearing) and transducer used for stimulus presentation. The results of this study demonstrate that ART's correlate too poorly with the LDL to permit ART's to be used as an objective measure of loudness discomfort.

Acoustic Impedance Tests↗
PubMedDate not supplied

The effects of various front-to-back ratios on the performance of directional microphone hearing aids.

Twenty-four sensorineural hearing-impaired adults were evaluated using four directional microphone hearing aids differing only in front-to-back ratios. The speech material utilized was the Synthetic Sentence Identification Message Competition Ratios of 0, -10, and -20 dB. The primary signal was presented from a 0 degree azimuth with the competing message was presented from a direct overhead location. The results revealed a systematic improvement in speech understanding as the size of the front-to-back ratio increased. This relationship was not significantly affected by the difficulty of the listening situation.

Adult↗
PubMedDate not supplied

Cervical bracing after trauma.

Because injudicious movement of the patient with a cervical spine and spinal cord injury can cause additional damage, the cervical spine of the trauma victim suspected of having such an injury must be immobilized at the scene of the accident. A review of the different movements occurring at different levels of the cervical spine indicates that different orthoses--rigid or soft collar, poster brace, cervicothoracic brace, halo appliance--vary in their effectiveness in restricting movement. The semirigid collar, because of its effectiveness in limiting movement and its ease of application, is recommended for immobilizing the cervical spine of a trauma victim.

Braces↗
PubMedDate not supplied

Urogenital complications of anterior approaches to the lumbar spine.

The superior hypogastric plexus of the sympathetic nervous system is the only major innervation of the urogenital system which is normally at risk in anterior exposures of the lower lumbar spine. When this is injured, one can expect to see disturbances of urogenital function with retrograde ejaculation or sterility in males. Failure of penile erection is not anticipated unless the patient has, in addition, advanced peripheral vascular disease. The superior hypogastric plexus may be spared by careful dissection about the iliac arteries and lumbosacral junction or by approaching the spine laterally through a retroperitoneal exposure.

Arthrodesis↗
PubMedDate not supplied

Cervical orthoses: a guide to their selection and use.

A large variety of cervical orthoses is available, but these may be divided into four basic groups. Although the orthoses in each group provide similar controls, each appliance has certain discrete advantages and limitations. The effectiveness of seven different cervical appliances in restricting motion in flexion-extension, lateral bending and rotation is presented. This information may be used to rationally select an orthosis to control specific clinical problems. A guide is formulated for selecting the orthoses for the control of various cervical injuries and postoperative problems.

Adult↗