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Biomedical subjects

T R Dillingham

Publications and source records attributed to T R Dillingham.

30 records · Page 2Linked to original sources
PubMed1992

Effect of lower limb on body propulsion.

The purpose of this study was to analyze and compare the effects of the leg during swing and stance phases of forward propulsion of the body for both men and women. Twelve able-bodied subjects, six men and six women, were studied with a Vicon(a) gait-analysis system. A two-dimensional, sagittal-plane biomechanical analysis featuring a link-segment model was used to determine the force at the hip in the horizontal direction. Integrating this force curve over time during the swing and stance gait phases produced linear impulses, representing swing and stance contributions to the propulsion of the body, and it allowed quantitative comparisons using student t and Fisher tests. The deceleration of the swing leg was found to be the major contributor to the forward propulsion of the body. The stance leg initially exerted the major restraining or negative impulse during early stance; then it generated a positive impulse during push-off in late stance. A typical pattern of gait impulses was defined for normal gait. Male and female gait impulses were not significantly different for all gait phases.

Adult↗
PubMedDate not supplied

Topical capsaicin for chronic neck pain. A pilot study.

Substance P is thought to be the principle neurotransmitter of nociceptive impulses in type C sensory neurons. Prolonged repeated applications of capsaicin cream depletes the sensory C-fibers of substance P. In an open-labeled prospective pilot study, 23 patients with chronic neck pain (greater than 3 mo) completed the study. Patients applied topical capsaicin (0.025%) cream four times a day to painful areas in the neck and shoulder girdle for a 5-wk treatment period. One patient dropped out because of intolerable burning. Statistically significant improvement was obtained in two primary outcome variables, the visual analog pain scale (P = 0.00013) and the pain relief scale (P = 0.002). Paired t tests failed to show a significant improvement in the McGill Pain Questionnaire. This study demonstrated that topically applied capsaicin cream may decrease subjective neck pain. A double-blind, placebo-controlled trial is needed to confirm this treatment effect.

Administration, Topical↗
PubMedDate not supplied

Statistical methods of computing reference values for side-to-side differences in nerve conduction studies.

This study uses theoretic derivations, statistical simulations, and empirical estimations to compare two ways of deriving reference values for side-to-side differences in nerve conduction parameters of healthy subjects. The two methods involve using the side-to-side differences (STSD) and the absolute values of the STSD (AVSTSD). The theoretic derivations showed that the population reference value of the AVSTSD is greater than the STSD reference values by 0.18%. Simulation studies showed that the AVSTSD yields greater sampling errors than the STSD method when establishing the reference values for nerve conduction parameters. However, the sampling variability is substantially reduced by using study samples of greater than 50, and the differences between the two methods in sampling errors are trivial as sample size approaches 100. Using H reflex (HR) and extensor digitorum brevis reflex (EDBR) clinical data, the two methods were compared. In contrast to the small theoretic differences in reference values, the AVSTSD method overestimated the reference value by 0.5 ms for the EDBR and 0.1 ms for the H reflex, when using data from a population sample, increasing the type II error (reducing sensitivity) for the EDBR. The STSD method is recommended for establishment of normal values and for clinical comparisons.

Electromyography↗
PubMedDate not supplied

Mylohyoid late responses elicited with intraoral stimulation.

Many disorders affect the trigeminal nerve, highlighting the need for electrodiagnostic methods to evaluate this cranial nerve. The purpose of this study was to develop and refine clinical nerve conduction techniques for examining mylohyoid late responses and to establish normative clinical data. Intraoral stimulation of the mylohyoid nerve was performed on normal volunteers using a pediatric stimulator taped to a tongue depressor. Mylohyoid direct and late responses were recorded with surface electrodes over the mylohyoid muscles. Mylohyoid late responses with supraorbital nerve stimulation and blink reflexes were also elicited. Fifty-four subjects, 65% females, with an average age of 39.2 (standard deviation, 13.4) yr, were studied. Direct mylohyoid responses were elicited in all subjects with a mean of 1.8 (standard deviation, 0.3) ms and amplitude of 4.1 (standard deviation, 1.4) mV. Late responses occurred in 94% ipsilaterally at an average latency of 32.4 (standard deviation, 6.5) ms and in 90% contralaterally at 32.4 (standard deviation, 5.6) ms. Two distinct late responses, the second occurring at an average of 72.3 (standard deviation, 12.4) ms with intraoral stimulation were noted in 25% of subjects. Only 11% of subjects had mylohyoid late responses with supraorbital stimulation. Blink (R1) reflexes occurred in 89% (10.9 ms; standard deviation, 0.7 ms), ipsilateral R2 responses in 88% (35.2 ms; standard deviation, 3.4 ms), and contralateral R2 responses in 69% (36.2 ms; standard deviation, 4.0 ms). Mylohyoid late responses are present in most normal subjects. The neuroanatomical pathways mediating these responses require delineation. These nerve conduction techniques may be useful in evaluating patients with suspected trigeminal nerve disorders.

Adult↗
PubMedDate not supplied

Effect of history and exam in predicting electrodiagnostic outcome among patients with suspected lumbosacral radiculopathy.

OBJECTIVE: To determine the extent to which the history and physical examination predict the outcome of the electrodiagnostic (EDX) evaluation in patients with suspected lumbosacral radiculopathy. DESIGN: Data for 170 subjects referred for low-back and lower limb symptoms were prospectively collected at five EDX laboratories. The sensitivity, specificity, positive and negative predictive values, and odds ratios were determined for symptoms and neurologic signs. RESULTS: Symptoms were not significantly associated with an EDX study or a lumbosacral radiculopathy. The physical examination was better at predicting that an EDX study would be abnormal in general than it was at predicting a lumbosacral radiculopathy in particular. Of those subjects with normal physical examinations, 15%-18% still had abnormal EDX findings. CONCLUSIONS: In a population of patients referred for an EDX study, the history and physical examination alone cannot reliably predict electrodiagnostic outcome.

Adolescent↗
PubMedDate not supplied

Symptom duration and spontaneous activity in lumbosacral radiculopathy.

OBJECTIVES: A long-held notion in the electrodiagnostic literature is that paraspinal muscles tend to show spontaneous activity (fibrillations and positive sharp waves) on needle electromyography, early on in a lumbosacral radiculopathy, and that more distal muscles become abnormal later in the disease process. The purpose of this study was to determine whether paraspinal muscle and other major proximal and distal muscle spontaneous activity is related to a lumbosacral radiculopathy symptom duration. METHODS: A multicenter, prospective study that collected standard information on history, physical examination, and electrodiagnostic findings in patients with electrodiagnostically confirmed lumbosacral radiculopathies was undertaken. RESULTS: Multivariate probit analyses of 96 patients identified with a lumbosacral radiculopathy showed no evidence of correlation between spontaneous activity in the paraspinal muscles and symptom duration. Symptom duration was also nonsignificant in nine of the remaining ten lower limb muscles analyzed. CONCLUSION: These findings emphasize the limitations of using symptom duration when interpreting electrodiagnostic findings in lumbosacral radiculopathy.

Action Potentials↗
PubMedDate not supplied

Importance of gadolinium enhancement when using MRI to evaluate spinal cord pathology.

Since its introduction, magnetic resonance imaging has become an indispensable diagnostic tool for the physiatrist evaluating potential spinal cord pathology. Despite ongoing advances in MRI technology and subsequent improved sensitivity, significant pathology can still be missed. In this article, we review the clinical role of contrast enhancement in visualizing many forms of spinal cord pathology.

Abscess↗
PubMedDate not supplied

Identifying lumbosacral radiculopathies: an optimal electromyographic screen.

OBJECTIVE: The objective of this study was to determine prospectively the optimal electromyographic screening examination of the lower limb that ensures identification of those lumbosacral radiculopathies that can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DESIGN: A prospective multicenter study was conducted from May 1996 to September 1997. Patients with suspected lumbosacral radiculopathy referred to participating electrodiagnostic laboratories were recruited and examined by needle electromyography using a standard set of muscles. Patients with electrodiagnostically confirmed lumbosacral radiculopathies were selected for analysis. Various muscle screens were tested against this group of patients with radiculopathies to determine the frequency with which each screen identified the patient with radiculopathy. RESULTS: There were 102 patients identified. When paraspinal muscles were one of the screening muscles, four-muscle screens identified 88-97% of the radiculopathies, five-muscle screens identified 94-98%, and six-muscle screens 98-100%. When paraspinal muscles were not part of the screen, identification rates were lower for all screens, and eight distal muscles were necessary to identify about 90% of the radiculopathies. CONCLUSIONS: Six-muscle screens with paraspinal muscles yielded consistently high identification rates. Studying additional muscles produced no improvements in identification.

Adult↗
PubMedDate not supplied

Lumbosacral radiculopathy screen. Optimizing the number of muscles studies.

The literature is unclear as to which muscles and how many are required for a sensitive lumbosacral radiculopathy (LSR) screen. A retrospective study of 247 electrodiagnostically confirmed LSRs in 201 patients over a 3-yr period was conducted to determine how many muscles were required to identify a LSR. All LSRs showed abnormal spontaneous activity (positive waves or fibrillation potentials) in two or more muscles innervated by the same nerve root level but different peripheral nerves. All cases were categorized by radiculopathy level, and the most frequently abnormal individual muscles were combined into different muscle screens. The frequency with which each muscle screen identified a radiculopathy was the frequency with which one or more muscles in the screen displayed abnormal spontaneous activity divided by the total number of radiculopathies. The paraspinal muscles (PM) alone identified 88% of LSRs. Without PM, two muscle screens identified only 14-68%, three muscle screens identified 37-89% and four muscle screens identified 45-92%. Including PM, three muscle screens identified 86-94% of LSRs, four muscle screens identified 91-97% and five muscle screens yielded 94-98% identification. Seven to ten muscle screens resulted in minimal improvements in identifying a LSR with 98-99% identification. We conclude that five muscle LSR screens, including PM, are sufficient to identify LSRs while minimizing patient discomfort and examiner time.

Adolescent↗
PubMedDate not supplied

Relationship between muscle abnormalities and symptom duration in lumbosacral radiculopathies.

A long held notion in the electrodiagnostic literature is that paraspinal muscles tend to show electromyographic abnormalities early on in a lumbosacral radiculopathy and that more distal muscles become abnormal later in the disease process. The purpose of this study was to determine whether paraspinal muscles and other major proximal and distal muscle abnormalities are related to lumbosacral radiculopathy symptom duration. A multivariate logit analysis of 139 patients (retrospectively identified) with electrodiagnostically confirmed lumbosacral radiculopathies was used to test these hypotheses. Maximum likelihood estimates showed no evidence of correlation between abnormal paraspinal muscles and symptom duration. Symptom duration was also insignificant for the remaining five lower limb muscles analyzed. We conclude that the probability of having electromyographic abnormalities is not related to symptom duration. A prospective study is needed to confirm these findings. Nonetheless, clinicians should use caution when interpreting electrodiagnostic findings based on symptom duration.

Adolescent↗