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Biomedical subjects

G H Kraft

Publications and source records attributed to G H Kraft.

At least 19 recordsLinked to original sources
PubMed1992

Dermatomal somatosensory evoked potentials in the diagnosis of lumbosacral spinal stenosis: comparison with imaging studies.

Dermatomal somatosensory evoked potentials (DSEPs) and computerized tomography/magnetic resonance (CT and/or MR) images were retrospectively analyzed to evaluate their relationship in the diagnosis of lumbosacral spinal stenosis (SS). Of 155 patients referred for DSEPs with a clinical suspicion of lumbosacral SS, 58 met the inclusion criteria. DSEP abnormality was defined as: (1) N1 latency absent or greater than 2.5 SD; (2) side-to-side latency difference greater than 2 SD; (3) amplitudes greater than 2 SD below the mean; or (4) amplitude ratio greater than 2 SD. Involvement of two or more DSEP levels by any of the above criteria was labeled multiple root disease (MRD). Involvement of one level was labeled single root disease (SRD). Images were reviewed independently by a neuroradiologist. Results revealed 54 subjects with SS by imaging; 42 had MRD and 8 had SRD by DSEPs. Sensitivity for MRD and SS was 78%, and for MRD plus SRD and SS was 93%.

Electromyography↗
PubMed1992

Techniques to improve function of the arm and hand in chronic hemiplegia.

We evaluated functional improvement in the upper limb of chronic (more than six months' duration) stroke patients who received one of two electrical stimulation treatments, conventional treatment, or no treatment. Twenty-two right-handed patients were assigned to one of four groups studied for 12 months posttreatment. Subjects received (1) EMG-initiated electrical stimulation of wrist extensors (EMG-stim), (2) low-intensity electrical stimulation of wrist extensors combined with voluntary contractions (B/B), (3) proprioceptive neuromuscular facilitation (PNF) exercises, or (4) no treatment. Subjects were treated for three months. Before treatment, upon completion of treatment, and three and nine months after treatment, subjects were evaluated by the Fugl-Meyer (FM) poststroke motor recovery test and by grip strength. Subjects also attempted three Jebsen-Taylor hand function tests and a finger tapping test at the same evaluation sessions, but many were unable to complete these tests. During the course of treatment, FM scores of subjects receiving PNF improved 18%, B/B improved 25%, and EMG-stim improved 42%. The aggregate FM improvement of the treated groups was significant from pretreatment to posttreatment, and the improvement was maintained at three-month and nine-month followups (all p less than .005). The treated subjects' improvement in grip strength was also maintained at both followups (p less than .10). In contrast, the control group showed no significant change in FM scores or grip strength. The four treated subjects who were able to perform the hand function tests and finger tapping at all four evaluations also improved on these tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Carpal tunnel syndrome: objective measures and splint use.

One hundred five adults with carpal tunnel syndrome (CTS) were studied to assess the efficacy of a neutral-angle wrist splint, and to identify criteria for splint referral. Ten observations before and after treatment were analyzed with descriptive and inferential statistics. After splint use, 67% of the subjects reported symptom relief. T-test comparison of sensory latency of values before and after treatment indicated improvement for the total group. Chi-square and t-tests failed to reveal significant differences between relief and no-relief groups for gender, affected hand, presence of concomitant conditions, duration of symptoms before treatment, age, length of time between pretreatment and posttreatment nerve conduction testing, initial nerve latency of motor and sensory fibers, or the difference between pretreatment and posttreatment sensory latencies. A significant difference was found for motor latency; the relief group improved and the no-relief group deteriorated. Data suggest that splinting is most effective if applied within three months of symptom onset. Those with damage to the wrist structures or median nerve were least responsive to splinting.

Adult↗
PubMed1990

Fibrillation potential amplitude and muscle atrophy following peripheral nerve injury.

Maximum peak-to-peak fibrillation potential amplitude was measured in 69 subjects between 7 days and 10 1/2 years post complete or partial peripheral nerve injury. Mean amplitude during the first 2 months was 612 muV; third and fourth months 512 muV, fifth and sixth months 320 muV. After the first year, no population of fibrillation potentials greater than 100 muV was recorded. The sciatic nerve was sectioned in 13 guinea pigs and animals studied up to 17 weeks. Fibrillation potential amplitude in gastrocnemius muscles declined paralleling that in humans. By the end of the study, type I fibers had lost almost half of their initial diameter and type II fibers had atrophied more than twice this amount. Fibrillation potential amplitude may be useful in estimating the time post nerve injury and appears to correlate with the surface area and fiber diameter of a type I muscle fiber.

Action Potentials↗
PubMed1990

Comparison of median and posterior tibial nerve somatosensory evoked potentials in ambulatory patients with definite multiple sclerosis.

Somatosensory evoked potentials (SEPs) were recorded for stimulation of both median nerves and both posterior tibial nerves in control subjects and in subjects with multiple sclerosis (MS) of several years' duration, who were ambulatory and not experiencing exacerbation. Documentation of peripheral nerve conduction revealed no abnormalities in any of the subjects. Centrally, abnormal responses to median and posterior tibial nerve stimulation were found at the spinal level and/or the scalp in nearly all MS patients. Using the latency of the initial negativity of scalp SEPs, posterior tibial SEPs were abnormal significantly more often than median SEPs. Calculations suggested a significant increase in spinal conduction time. The high incidence of abnormal SEPs does not support any substantial physiological recovery in this group of MS patients.

Adult↗
PubMed1990

Laterality of performance in fingertapping rate and grip strength by hemisphere of stroke and gender.

To determine whether individuals with unilateral cerebrovascular accident (CVA) have different motor abilities depending on hemisphere of lesion, we tested fingertapping rate (TAP) and grip strength (GRIP) in 20 right-handed right (R) and left (L) chronic CVA survivors and 19 right-handed age- and gender-matched controls. GRIP and TAP tests are common measures of motor function selected to distinguish rapid repetitive vs sustained performance. As expected, performance was significantly worse for contralateral-to-lesion arms than for control arms (p less than .001). Ipsilateral-to-lesion performance confirmed predictions of lateralized motor disabilities: R-GRIP in R-CVA survivors was inferior to R-GRIP in controls (p less than .05); L-TAP in L-CVA survivors was inferior to L-TAP in controls (p less than .01). In addition, male CVA survivors had the enhanced abilities predicted in the converse tests: R-TAP in R-CVA men was superior to R-TAP in controls (p less than .10); L-GRIP in L-CVA men was superior to L-GRIP in controls (p less than .01). It was concluded that individuals move differently depending on hemisphere of stroke, and some implications for the poststroke motor rehabilitation program were discussed.

Aged↗
PubMed1989

Quantification of gaps in the EMG interference pattern in chronic hemiparesis.

This study presents a quantification of the impersistence in the EMG interference pattern (IP) produced during maximal effort by patients with chronic hemiparesis. Monopolar needles were used to record from the flexor carpi radialis (FCR) and extensor carpi radialis longus (ECR) muscles of both the paretic and non-paretic sides of 19 patients with a history of unilateral CVA and 10 healthy control subjects during maximal voluntary isometric wrist flexion or extension. We found more gaps in the IP and fewer total seconds of EMG activity in paretic than in non-paretic or control forearm muscles. The number of gaps was similar in paretic FCR and ECR, but the reduced active time in paretic ECR indicates proportionally more gaps per second of EMG activity. This method provides quantitative measures of both the lapses (gaps in the IP during maximal effort and the inability to sustain EMG activity (total seconds) during long contractions. The latter measure is sufficiently sensitive to distinguish the greater impairment of a paretic wrist extensor than a paretic wrist flexor muscle, and both may prove to be valuable for future comparisons of the severity of paresis and the progress of recovery. These results represent the first quantitative confirmation of previous qualitative descriptions of impersistent recruitment.

Aged↗
PubMed1988

Recruitment and termination of electromyographic activity in the hemiparetic forearm.

Motor unit control measured by timed recruitment and termination of intramuscular electromyographic (EMG) activity provides muscle-specific quantification of deficits of the arm in chronic hemiparesis. Latencies to recruitment and termination of EMG activity of flexor carpi radialis and extensor carpi radialis longus were recorded from nine stroke patients and five age- and sex-matched control subjects, in response to buzzer signals, during maximal isometric wrist flexion and extension. Both agonist and antagonist recruitment times were slower in paretic than in control forearms (p less than .01). Termination of EMG activity occurred earlier in paretic forearms, primarily because of inability to maintain a prolonged muscular contraction. The effects of the variable lengths of testing trials reinforced these conclusions. The paretic extensor carpi radialis longus showed the greatest impairment with a very long latency to contract, and frequent failure to maintain a contraction. This study presents a new method of quantifying a common clinical problem in rehabilitation medicine.

Aged↗
PubMed1988

Co-contraction in the hemiparetic forearm: quantitative EMG evaluation.

Co-contraction of antagonist muscles is a recognized clinical phenomenon in patients surviving a cerebrovascular accident. Yet, discrepancies persist in the literature as to whether or not antagonist electromyographic activity is increased in hemiparesis. We have developed a technique to obtain simultaneous counts of motor unit activity in a wrist flexor and extensor muscle using monopolar needle electromyography. Stable stroke patients and age/sex matched control subjects were tested during maximal voluntary isometric wrist flexion and extension. Fewer agonist events (p less than 0.05) and more antagonist events (p less than 0.10) were counted in paretic than in control muscles. A co-contraction ratio of antagonist activity to total (agonist and antagonist) activity was much greater for patients than controls (p less than 0.01). We conclude that both agonist recruitment and antagonist inhibition are impaired in the hemiparetic arm.

Aged↗
PubMed1986

Disability, disease duration, and rehabilitation service needs in multiple sclerosis: patient perspectives.

The purpose of this study was to determine the medical, psychologic, social, and vocational needs of individuals with multiple sclerosis (MS) and to evaluate these needs with respect to age, disease duration, sex, and disability level. Individuals with MS in western Washington state were asked to participate by responding to a mailed questionnaire. Six hundred fifty-six completed the questionnaire of more than 250 variables covering symptoms, diagnosis, adjustment, service use and service need were found in this population. Medical needs, with the exception of bladder management and physical therapy, appeared well met. However, counseling and vocational needs appeared less well met. The perceived need for most medical and community services was correlated with increasing disability as might be expected. However, the need for vocational and psychologic services was not related to the level of disability but to the age of the patients and the recency of MS diagnosis.

Activities of Daily Living↗
PubMed1985

Expressive communication disorders in persons with multiple sclerosis: a survey.

The purpose of this study was to survey individuals with multiple sclerosis to determine (1) the presence and severity of their expressive communication disorders, (2) the extent expressive communication problems interfere with employment, and (3) the frequency of using communication augmentation equipment. An eight-page questionnaire was distributed to 656 persons diagnosed as having multiple sclerosis, who returned completed questionnaires. Twenty-three percent of the total sample reported the presence of "speech or other communication problems." Four percent of the total sample indicated that strangers were unable to understand them. Of this group 28.8% reported that they used communication augmentation equipment.

Adult↗
PubMed1984

Pyridoxine metabolism in carpal tunnel syndrome with and without peripheral neuropathy.

The role of insufficient pyridoxine as an etiologic factor in the development of carpal tunnel syndrome (CTS) has been reported and has led to the empirical use of pyridoxine to treat CTS. Previous studies have not employed standardized electrodiagnostic criteria to objectively determine the presence of CTS or to rule out peripheral neuropathy (PN). The present study categorized subjects with symptoms suggestive of CTS into four groups by standardized electrodiagnostic criteria: (1) CTS, (2) PN, (3) CTS and PN, (4) normal. At least seven subjects were in each group. Erythrocyte glutamine oxaloacetic acid transaminase (EGOT) activity with and without in vitro enhancement with pyridoxal phosphate was used as a means of identifying subjects with and without pyridoxine metabolic abnormalities. A significant difference in pyridoxine metabolic activity (PMA) was found between groups by both chi square (p less than 0.05) and analysis of variance (p less than 0.05). Further evaluation showed that this difference was associated with the presence or absence of PN (p less than 0.05). There was no difference in PMA when groups were separated on the basis of CTS. Results showed that a PMA abnormality was a factor highly correlated with the presence of PN but not CTS. This finding suggested that the positive response reported previously in subjects with CTS taking supplemental pyridoxine may actually be related to an unrecognized PN, which was compounding the symptomatology.

Aspartate Aminotransferases↗