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Biomedical subjects

R P Lehr

Publications and source records attributed to R P Lehr.

At least 19 recordsLinked to original sources

Testing knowledge of human gross anatomy in medical school: an applied contextual-learning theory method.

The traditional gross anatomy laboratory experience, with modifications in evaluations that we outline later, meets the criteria of contextual-learning theory, expands the repertoire of core objectives we identify for our students, and may increase the likelihood of cognitive permanence of anatomical data. Our subjects included approximately 54 first-year medical students from each of three sequential class years (1996, 1997, 1998). As an alternative to more typical written and practical exams, examinations in a major portion of our gross anatomy program consist of two approximately 30 minute oral expositions by each student to his or her peers and a faculty member. Students demonstrate specific detail on cadaver, x-ray, cross sections, or a model. Clinical applications, spatial relationships, nomenclature, and functions are strongly emphasized. The results of this teaching approach to the utilization of anatomical knowledge in clinical situations requires further assessment: however, new attributes have been afforded our students with implementation of the present program: First, students learn anatomical detail equally well as the students of the more traditional system (based on board exam results). Second, students who completed the program indicate that this approach provides a useful simulation of what is expected later in their training. Third, students gradually gain confidence in verbal presentation, they demonstrate cognitive synthesis of separate conceptual issues, they retain information, and they are quite visibly more enthusiastic about anatomy and its importance in medicine. Our program demonstrates that the learning of applicable human anatomy is facilitated in a contextual-learning environment. Moreover, by learning anatomy in this way, other equally beneficial attributes are afforded the medical student, including, but not limited to, increases in communication skills, confidence in verbal presentation, synthesis of anatomical concepts, appreciation of the clinical importance of anatomy, and the general development of professionalism.

Anatomy↗

Post-traumatic syringomyelia.

Post-traumatic syringomyelia was previously thought to be an infrequent but serious sequel to spinal cord injury. Clinical and CT studies have shown an incidence of between 1% and 5%, but more recently MRI has suggested an incidence of up to 22%. Twenty spinal cords have been examined after death from two days to 43 years after injury. Four had syrinxes, 20% of the series, approaching the incidence found by MRI. The acute and chronic pathological changes after trauma are described. Post-traumatic syringomyelia seems to develop from cores of necrotic tissue (myelomalacic cores) rather than lysis of haematoma. The mechanism of extension of syrinxes remains unexplained.

Adolescent↗

Post-acute rehabilitation outcome: relationship to case-management techniques and strategy.

Successful outcome for the traumatically brain-injured (TBI) patient is dependent on both a productive clinical therapy program and an effective case-management strategy by the carrier. This retrospective study focuses on identifying those case-management techniques which contributed to improvement in the disability, living, and occupational status of patients in a post-acute rehabilitation program. Statistical analysis indicated a positive relationship between two case-management factors and improved patient outcome. Additional analysis demonstrated predictive qualities of specific admission data for patient program cost. A review of these case-management techniques and their impact on discharge disability, living, and occupational status will be discussed.

Adult↗

Electromyographic evidence of a multiple motor system: implications for apraxia.

Geschwind (1975) postulated that a multiple motor system accounts for a discrepancy in apraxias in response to commands for truncal and limb movements. Kuypers (1968) provided experimental evidence of a multiple motor system in primates. We present evidence of this multiple motor system in the form of Fourier-transformed electromyographic data in humans of the predominantly short duration motor units for discrete control in hand musculature and the predominantly longer duration motor units in the truncal musculature. Furthermore, the right and left erector spinae muscles had different Fourier-transformed electromyographic data which, in our opinion, represent the medial motor system used by apraxias.

Adult↗

Embryological considerations of distinctive feature theory.

The role of the physiology is emphasized here, perhaps to the eventual denial of the importance of the acoustic cues involved at these stages. The acoustic cues are the result of the physiology and are a further development of the features of speech. The selection of the sounds of babbling is a function of the physiological readiness and is an internal function [Locke, 1983]. Sounds are produced that are not used in final adult speech [Locke, 1983]. It is the acoustic cues of the environment that perhaps cause the 'babbling drift' toward adult speech of the environment [Brown, 1958]. In line with the above-mentioned ideas regarding branchial arch development, most of the components of the outer and middle ear are derivatives of the first branchial arch, which though limited musculature is involved, especially for sound perception, might downplay the role of acoustics at these earliest stages even further. If it can be said that cortical organization and representation development follow a similar sequence as is evidenced from the branchial arches and their derivatives, the importance of acoustic stimuli, at this point, would be even further questioned for these early stages. The assumption should be made that a muscle or muscle group does not function prior to this established branchial arch pair sequence. The major distinction here has been utilization of the structures in a 'conscious', deliberate, voluntary manner with a specific goal in mind. The babbling and even feeding that children undergo provides evidence that these structures function perhaps long before any sequence of branchial arch pair developmental sequence can be applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Branchial Region↗

An electromyographic study of the abdominal muscles during postural and respiratory manoeuvres.

A method was developed for making EMG recordings from the four individual muscles of the anterior abdominal wall. It was then demonstrated that these muscles have different and distinguishable actions on trunk movement, but act together in breathing. The level of ventilation at which the abdominal muscles become active in expiration was shown to be posture dependent.

Abdominal Muscles↗

An electromyographic study of the abdominal muscles of tetraplegic patients.

Bipolar fine wire electrodes were used to make electromyographic (EMG) recordings of the abdominal muscles of 8 stable complete tetraplegic patients. Synchronous recordings were made of ventilation, and in 5 subjects an oesophageal electrode was used to record diaphragm EMG. In all 8 subjects we demonstrated phasic inspiratory EMG activity which we have shown to be localised to the abdominal muscles. We believe that this activity was triggered by stretching of the abdominal wall on inspiration. Its effect will be to decrease abdominal wall compliance allowing the diaphragm to generate greater intra-abdominal pressure as it descends, thus promoting inflation of the lower rib cage.

Abdominal Muscles↗

Biomechanical analysis of human arm stabilization during force production.

The activity of muscles of the human arm can produce force against an external system which may be interpreted as a directional force and a stabilizing force. This paper investigated the relationship between muscle activity in the human arm during both maximal and submaximal external force development against a handle. Three different handle arrangements were studied; fixed, free to move in the horizontal direction and free to move in the vertical direction. Ten subjects were utilized. Analyses of angle, force and electromyographic data revealed that the increased muscle activity at the wrist when compared with action against the movable external system was a function of the stabilizing force and not of directional force production. It is suggested that the extensor muscles of the wrist are the initiators of the stabilizing force as well as the major stabilizers of the wrist joint during the resultant force production against the handle.

Arm↗

Electromyographic investigation of the diaphragm and intercostal muscles in tetraplegics.

Local electromyographic activity has been demonstrated in the intercostal muscles of tetraplegic patients by using a combination of surface, fine-wire and intra-oesophageal diaphragmatic electrodes. This activity is first present and most evident in the lower chest, the point of maximum deformation in the tetraplegic's thorax. In patients with long standing injury the activity is present and prominent in the more superior intercostal muscles. We believe this activity to be reflex in character and that it develops and facilitates over time, so improving the ventilatory capacity of tetraplegics.

Adult↗

Dyspnoea during generalised spasms in tetraplegic patients.

Dyspnoea during generalised spasms is reported in three tetraplegic patients. Intraoesophageal electromyographic evidence strongly suggests that the dyspnoea is a result of diaphragmatic spasms. Utilisation of this EMG technique in other tetraplegic patients may add to our knowledge of variations in the distribution of the phrenic nerve nucleus within the spinal cord.

Adult↗

An electromyographic study of the human lateral pterygoid muscles.

An electromyographic investigation of the lateral pterygoid muscles was undertaken to determine their activity relative to isolated and functional movements of the mandible. Daerally in the lateral and medial pterygoid muscles. Surface electrodes were placed bilaterally on the skin over the temporalis and masseter muscles. Our data strongly suggest that separate roles for the superior and inferior heads of the lateral pterygoid cannot be supported electromyographically. In addition, the lateral pterygoid is active in protrusive movements, including an incisor clench, and not active in retrusion or a molar clench. Both lateral pterygoid muscles initiate depression of the mandible and the contralateral muscle initiates a lateral transversion. The ipsilateral activity present is not sufficient to be an active stabilizer of the temporomandibular joint. In the chewing cycle, the lateral pterygoids are bilaterally active, both in alternation with and overlapping the elevating musculature. The sequence of the lateral pterygoid activity in the chewing cycle is led by the ipsilateral lateral pterygoid muscle.

Adult↗

Gross morphological brain differences between Wistar-Kyoto and spontaneously hypertensive rats.

The dissected brains of twelve age-matched rats, six spontaneously hypertensive (SH) and six normotensive (WKY), were examined for quantitative gross morphological differences. The spontaneously hypertensive rats were found to have a significantly smaller mesencephalic region when viewed from the external surfaces. This altered morphology has implications in the stereotaxic placement of lesions or cannulae.

Animals↗

Musculus levator glandulae thyroideae: an observation.

An occurance of M. levator glandulae thyroideae is reported and its frequency of appearance is established at one in 203 cases (0.49%). The importance of this and similar observations of anomalous gross morphological structures are discussed.

Female↗

Duration of task: an indicator of differentiation between motoneuron pools.

Sustaining an isometric contraction at a percentage of maximum contraction value prior to fatigue is significantly longer for the dominant arm than the non-dominant arm as reanalysis of data shows. This peripheral motor parameter which differentiates handedness as reflected in motoneuron pools may clarify the relationship between contralateral motor function and functional cerebral lateralizations.

Arm↗