The clinical reliability of brain stem auditory evoked responses.

Auditory evoked responses thought to originate in the brain stem were investigated in patients with and without good evidence of brain stem pathology, and in healthy volunteers. The purpose of the investigation was to find a method of quantifying these evoked responses which would be clinically useful. The best quantitative measure was the latencies of certain peaks in the evoked response considered in combination. This measure indicated abnormal brain stem evoked responses in 64% of patients with good independent evidence of brain stem pathology; 23% of patients with equivocal independent evidence of brain stem pathology; and 0% of healthy volunteers.

Tension and creep phenomena in peripheral nerve.

Tension introduced into peripheral nerves during their surgical repair may reduce the success of this procedure. Two mechanical factors are important; the tension required to effect a repair, and the rate at which this tension changes after surgery. These two factors have been investigated in the rat sciatic nerve. The results show an increasing resistance to elongation of the nerves with increasing tension. Under a constant elongation the tension in the nerves reduces by about 30 per cent in the first 10 minutes and by a small amount in the following 20 minutes.

Neuropsychological functioning in patients with borderline personality disorder.

Although results have been variable, studies suggest that individuals with borderline personality disorder (BPD) exhibit cognitive deficits suggestive of frontal- and temporal-lobe dysfunction. Patients diagnosed with BPD (n = 18) using two structured interviews, and who were carefully screened for neurological and substance-use disorders, were compared to depressed patients (n = 18) and a nonpsychiatric control group (n = 18) on a series of neuropsychological tasks. The role of emotion on cognitive functioning was assessed by including emotional stimuli and interference on several of the tasks. Little support was found for the neurobehavioral hypothesis of BPD. The BPD group performance did not differ from the normal group on most tasks of executive functioning or memory, and the introduction of emotional stimuli did not impair performance. The depressed group performed less effectively than the other groups. Reasons for variable findings and factors affecting the cognitive functioning of patients with BPD are discussed. There may be considerable heterogeneity in the cognitive functioning of BPD patients, with those exhibiting significant cognitive deficits comprising only a subgroup.