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Biomedical subjects

A Cassvan

Publications and source records attributed to A Cassvan.

10 recordsLinked to original sources
PubMed1990

Brainstem auditory evoked potential studies in patients with tinnitus and/or vertigo.

The significance of brainstem auditory evoked potential (BAEP) studies in patients with vertigo and/or tinnitus is not universally recognized. In this study, 29 patients with these complaints as the presenting symptoms were evaluated with BAEPs, some of them as part of a work-up for a hearing and vertigo center. Case reports are presented. Absolute and interpeak latencies were related to patients' demographics and to stimulation parameters. Factors that correlated with increased numbers of abnormalities included male gender and higher stimulation rates (30 or 40/sec). Patient age and polarity of the stimulus had no major significance; neither did findings on either the right or left side. Overall, the percentage of cases with abnormalities was high (86.2%). This study confirms the importance of BAEPs in patients with vertigo and/or tinnitus. Furthermore, it is recommended that repeated trials be performed using a variety of parameters in order to facilitate the emergence of subtle abnormalities that would otherwise be missed.

Adult↗
PubMed1988

Median and radial sensory latencies to digit I as compared with other screening tests in carpal tunnel syndrome.

Fifty two patients with suspected carpal tunnel syndrome were evaluated electrodiagnostically by using a variety of screening tests. The criteria of normalcy were as follows: distal median motor latency lower than 4.2 ms, distal median sensory latency wrist-to-third finger at 14 cm higher than 3.2 ms for the onset and than 3.8 ms to the peak, median sensory conduction velocity wrist-to-palm at 7 cm higher than 40 m/s peak-to-peak and difference between median and radial sensory latencies wrist-to-first digit at 11 cm using an intermediate position as site of stimulation and measured peak-to-peak ("bactrian sign") higher than 0.4 ms. Other tests such as median-ulnar comparison using finger 4 were considered less reliable based primarily on the frequent association of carpal tunnel syndrome and Guyon canal entrapment. Carpal tunnel syndrome was confirmed in 49 of 52 suspected cases (94.2%) by at least one abnormal screening test. Bilateral involvement was noted in 65.3% of the cases (32 patients). The "bactrian" (two-hump camels) sign was the single most sensitive test used, being positive in 83.7% of cases. The second most sensitive test was median SNAP (wrist-to-finger) latency and the third, sensory conduction velocity across the carpal tunnel.

Adult↗
PubMed1986

Ulnar nerve involvement in carpal tunnel syndrome.

This is a retrospective study of the involvement of the ulnar nerve in patients with electrodiagnostic evidence of carpal tunnel syndrome as defined by median sensory nerve action potential (SNAP) greater than 3.6msec at the wrist and/or motor distal latency in excess of 4.3msec. The study included 248 patients, 63 (25%) with unilateral and 185 (75%) with bilateral carpal tunnel syndrome. The electrodiagnostic criteria for ulnar nerve involvement was a SNAP peak latency greater than 3.7msec and/or motor distal latency in excess of 4.2msec. One hundred fourteen patients (46%) had delayed ulnar SNAP peak at the wrist; of these, 100 cases had bilateral ulnar nerve involvement and 14 had unilateral abnormalities. Slowing of the motor nerve conduction velocity for the elbow-wrist segment was noted in 24% and 15% of the study group for the median and ulnar nerves, respectively. An incidental finding was the presence of "double crush syndrome" in 35 patients (14%). The results of this study suggest the frequent association of ulnar nerve involvement at the wrist for sensory fibers and carpal tunnel syndrome.

Action Potentials↗
PubMed1976

Lateralization in stroke syndromes as a factor in ambulation.

Lateralization should not be ignored in any rehabilitation program for patients with stroke syndromes. Despite the known differences resulting from the localization in the dominant versus the nondominant hemisphere (spatial perception, speech, etc.), practical application of this knowledge in gait training is sparse. The authors looked into different stages of ambulation and the time sequence between these stages and the onset of disease. Standing and walking in parallel bars and outside, as well as elevation activities were given numerical values in an effort to assess abilities quantitatively. The assessment of each patient was recorded graphically (stage of gait against time) and then the different graphs were summated in order to form a common right hemiparetic versus left hemiparetic curve. This study of 236 out of 298 patients (129 left hemiparetics and 107 right ones) showed the following: (1) The right hemiparetics progressed more rapidly in all stages of ambulation, statistically significant figures being obtained for the first two stages; (2) a greater percentage of right versus left hemiparetics reached the assigned levels of ambulation: and (3) 89% out of the 236 patients included in our study were able to ambulate in parallel bars, 81% outside the bars and 38.5% were proficient in stair climbing. Out of the original total number of patients (298), 64% were able able to ambulate outside the bars.

Adolescent↗
PubMedDate not supplied

Combined effect of click rate and stimulus polarity on BAEP latencies.

Previous studies addressed themselves to the effect of different parameters on the brainstem auditory evoked potentials (BAEPs). Of special interest were the repetition rate and the click polarity, both able to influence significantly the results. While previous contributions studied these two parameters separately, the present investigation is concerned with their combined effect, non-parametric statistical analyses allowing simultaneous consideration. 37 patients, 21 females and 16 males, with an age range of 20 to 95, carrying different diagnoses, were studied using rarefaction as well as condensation polarities, 10/sec as well as 30/sec repetition rates. Abnormalities present with only one stimulus polarity and repetition rate but not with another combination were present in 24 cases for polarity dependent changes (64.9%) and in 25 (67.4%) cases for repetition rate dependent ones. Generally 30/sec repetition rate yielded longer latencies when repetition rates were kept constant. The combination of condensation clicks and high repetition rates revealed a strong correlation with higher latencies.

Adult↗