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Biomedical subjects

J F Connolly

Publications and source records attributed to J F Connolly.

At least 109 records · Page 6Linked to original sources
PubMed1986

Evaluation of the Noiles hinged knee prosthesis. A five-year study of seventeen knees.

The Noiles hinged knee prosthesis has been reported to diminish sheer and tensile loading on the cement-bone interface. Theoretically, this should eliminate the complication of loosening, commonly reported in hinged total knee prostheses. We reviewed the cases of all of the patients who have been treated with the Noiles knee prosthesis at our institution. Eighteen knees in fourteen patients were available, seventeen of which were followed for more than five years. Although all of the prostheses did well initially, ten knees in eight patients (56 per cent) had failed by an average of thirty-two months postoperatively. These eight patients included four of the five who weighed more than ninety kilograms and all of those who had had a prior arthroplasty. The failures were clearly defined along the lines of sex distribution. Measurements on the radiographs showed a significant difference between sexes in the metaphyseal diameter and thus in the percentage of the femoral canal that was filled by the prosthesis and cement. We concluded that prosthetic design must incorporate cortical cement support to reduce stress at the cement-bone interface, especially in a medullary canal with a larger diameter.

Adult↗
PubMed1985

Pathway and hemispheric differences in the event-related potential (ERP) to monaural stimulation: a comparison of schizophrenic patients with normal controls.

Previous research has established the stability of the contralateral dominance effect of the auditory temporal N120 peak amplitude. The purpose of this experiment was to examine event-related potential (ERP) asymmetries in schizophrenia, with particular reference to this contralateral dominance phenomenon. Ten unmedicated schizophrenic patients and ten controls heard a series of monaural tones, with no task requirements, while EEG was recorded from Cz, Pz, T3, and T4 referred to linked earlobes. Patients were characterized by smaller N120 amplitudes than controls, an effect that was slightly more pronounced at temporal sites. Patients failed to show the normal N120 contralateral dominance effect. Hemisphere asymmetry ratios revealed that 50% of the patients showed ipsilateral dominance in the auditory pathways. Furthermore, the hemisphere asymmetries (whether ipsilaterally or contralaterally dominant) seen in patients were significantly greater than for controls. These data offer a new level of explanation for schizophrenic performance abnormalities in dichotic listening paradigms and an explanation for for the apparent dichotomy in patient performance between exaggerated right ear advantage (REA) and left ear advantage (LEA).

Acoustic Stimulation↗
PubMed1985

Common avoidable problems in nonunions.

Fracture-healing problems today occur predominantly in the weight-bearing tibia and femur. This review of 83 lower-limb nonunions out of a series of 100 fracture-healing problems identified avoidable causes in 30%. These included rigid fixation, which produced fracture gap, fibulectomy, which destabilized the tibia, and soft-tissue procedures, which impeded fracture management. The significance of these factors was evident when treatment to avoid the above-noted adverse factors did produce union. The fact that complications occur with certain techniques does not interdict their proper use. However, critical analysis of a large number of cases suggests the following three principles for avoiding nonunion: (1) Rigid fixation eliminates the critical external callus response of the first six weeks after fracture. Consequently, less than rigid fixation obtained with functional fracture braces or intramedullary rods, which maximize external callus and avoid fracture distraction, is generally preferable for weight-bearing bones. (2) Fibulectomy may encourage impaction across a tibial fracture gap. However, the resection should be performed well away from the tibial fracture site, thereby avoiding tibial instability. (3) With the open fracture, priority of management should be given to achieving fracture union rather than to absolute soft-tissue coverage. No fracture in this series failed to heal because of exposed bone.

Adult↗
PubMed1984

The augmenting/reducing phenomenon in the auditory evoked potential.

Auditory evoked potentials (AEPs) were recorded to 4 intensities of tones (70, 80, 90, 100 dB) in 22 normal subjects. Augmenting (generally increasing amplitude with increasing stimulus intensity) and reducing (a levelling off or decrease in amplitude with increasing stimulus intensity) were found to occur at both central (Cz, C3, C4) and temporal (T3, T4) placements, regardless of which peak or peak-through measure was examined. There were generally low levels of agreement between central amplitude/intensity response patterns and those at temporal placements. An individual was seldom classified the same way (i.e. augmenter or reducer) when the augmenting or reducing was assessed using different AEP measures. These results suggest that in the AEP the suitability of the conventional definition and the validity of certain interpretations of augmenting/reducing are questionable.

Adult↗
PubMed1984

Schizophrenia and spectral analysis of the visual evoked potential.

Power spectral analysis was performed on the visual evoked potentials (VEPs) recorded in response to flashes of different intensity in both unmedicated schizophrenic and normal subjects. At occipital locations (O1, O2), schizophrenics showed less power than normals in the 10-14 Hz frequency range. In the 18-22 Hz range, schizophrenics showed under-activation in the left hemisphere and over-activation in the right. At temporal locations (T3, T4), schizophrenics showed abnormal (left greater than right) hemisphere patterns of activation in 10-14 Hz and 18-22 Hz ranges. There were no group differences in relationships between power and intensity changes at vertex (Cz). The results suggest abnormal cortical-subcortical interactions during analysis of visual information in schizophrenia.

Adult↗