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R Rolke

Publications and source records attributed to R Rolke.

9 recordsLinked to original sources
PubMed2006

Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): standardized protocol and reference values.

The nationwide multicenter trials of the German Research Network on Neuropathic Pain (DFNS) aim to characterize the somatosensory phenotype of patients with neuropathic pain. For this purpose, we have implemented a standardized quantitative sensory testing (QST) protocol giving a complete profile for one region within 30 min. To judge plus or minus signs in patients we have now established age- and gender-matched absolute and relative QST reference values from 180 healthy subjects, assessed bilaterally over face, hand and foot. We determined thermal detection and pain thresholds including a test for paradoxical heat sensations, mechanical detection thresholds to von Frey filaments and a 64 Hz tuning fork, mechanical pain thresholds to pinprick stimuli and blunt pressure, stimulus/response-functions for pinprick and dynamic mechanical allodynia, and pain summation (wind-up ratio). QST parameters were region specific and age dependent. Pain thresholds were significantly lower in women than men. Detection thresholds were generally independent of gender. Reference data were normalized to the specific group means and variances (region, age, gender) by calculating z-scores. Due to confidence limits close to the respective limits of the possible data range, heat hypoalgesia, cold hypoalgesia, and mechanical hyperesthesia can hardly be diagnosed. Nevertheless, these parameters can be used for group comparisons. Sensitivity is enhanced by side-to-side comparisons by a factor ranging from 1.1 to 2.5. Relative comparisons across body regions do not offer advantages over absolute reference values. Application of this standardized QST protocol in patients and human surrogate models will allow to infer underlying mechanisms from somatosensory phenotypes.

Adolescent↗
PubMed2006

Left-hemispheric dominance for articulation: a prospective study on acute ischaemic dysarthria at different localizations.

Dysarthria is a frequent symptom in cerebral ischaemia. However, speech characteristics of these patients have not previously been investigated in relation to lesion site in a prospective study. We investigated the auditory perceptual features in 62 consecutive patients with dysarthria due to a single, non-space-occupying cerebral infarction confirmed by MRI. Standardized speech samples of all patients were stored within 72 h after stroke onset using a digital tape recorder. Speech samples were assessed independently by two experienced speech therapists, who were unaware of the clinical and neuroradiological findings, using an interval scale ranging from 0 to 6. Separately assessed were features of articulation, phonation, prosody, and the global severity for a total of 31 items. Extracerebellar infarctions (85.5%) were located in the lower motor cortex (14.5%), striatocapsular region (46.8%) and base of the pons (24.2%). Isolated cerebellar infarctions were present in 14.5% of patients. There was a strong correlation between the findings of both examiners, showing identical scores, or only minor differences (<1 on the assessment scale) for 80% of all items. The average severity of dysarthria was 2.9 +/- 1.3. Articulatory abnormalities were the predominant deviation characteristics, affecting in particular the production of consonants. However, phonatory and prosodic abnormalities were also frequently observed speech characteristics. As revealed by factor analysis of speech characteristics the total severity of dysarthria was mainly influenced by the impairment of articulation. Speech parameters describing characteristics of articulation and prosody showed significant side-to-side and area differences, while this effect was lacking for any voice parameter. Left cerebral lesions showed a more severe overall impairment of speech and articulation, independent of lesion topography. Thirty-eight of 62 patients were available for follow-up. Speech evaluation showed normal speech within weeks in 15 out of 38 patients (39.5%). In the other 23 patients overall severity of dysarthria was mild. This is the first prospective study which describes speech characteristics of dysarthria due to acute unilateral cerebral infarctions. We could demonstrate that dysarthria in extracerebellar infarctions was more frequently caused by left-sided lesions and that the severity of dysarthria was more pronounced in left-sided lesions independent from lesion topography. All extracerebellar lesions were located along the course of the cortico-bulbar tract fibres. Compatible with a common pathophysiological basis of dysarthria in these patients, none of the 31 speech items differed significantly between subcortical and brainstem lesions.

Acute Disease↗
PubMed2006

Quantitative sensory testing: a comprehensive protocol for clinical trials.

We have compiled a comprehensive QST protocol as part of the German Research Network on Neuropathic Pain (DFNS) using well established tests for nearly all aspects of somatosensation. This protocol encompasses thermal as well as mechanical testing procedures. Our rationale was to test for patterns of sensory loss (small and large nerve fiber functions) or gain (hyperalgesia, allodynia, hyperpathia), and to assess both cutaneous and deep pain sensitivity. The practicality of the QST protocol was tested in 18 healthy subjects, 21-58 years, half of them female. All subjects were tested bilaterally over face, hand and foot. We determined thermal detection and pain thresholds including a test for the presence of paradoxical heat sensations, mechanical detection thresholds to von Frey filaments and a 64-Hz tuning fork, mechanical pain thresholds to pinprick stimuli and blunt pressure, stimulus-response-functions for pinprick and dynamic mechanical allodynia (pain to light touch), and pain summation (wind-up ratio) using repetitive pinprick stimulation. The full protocol took 27+/-2.3 min per test area. The majority of QST parameters were normally distributed only after logarithmic transformation (secondary normalization) except for the frequency of paradoxical heat sensations, cold and heat pain thresholds, and for vibration detection thresholds. Thresholds were usually lowest over face, followed by hand, and then foot. Only thermal pain thresholds, wind-up ratio and vibration detection thresholds were not significantly dependent on the body region. There was no significant right-to-left difference for any of the QST parameters; left-to-right correlation coefficients ranged between 0.78 and 0.97, thus explaining between 61% and 94% of the variance. This study has shown that a complete somatosensory profile of one affected area and one unaffected control area, which will be necessary to characterize patients with a variety of diseases, can be obtained within 1 h. Case examples of selected patients illustrate the value of z-transformed QST data for an easy survey of individual symptom profiles.

Adult↗
PubMed2005

The unpleasantness of tonic pain is encoded by the insular cortex.

OBJECTIVE: Muscle pain differs from skin pain with respect to quality, accuracy of localization, and unpleasantness. This study was conducted to identify the brain regions associated with the affective-motivational component of tonic skin and muscle pain. METHODS: Forty healthy volunteers were investigated in three groups with different F-18 fluorodeoxyglucose PET activation scans. A verbal rating scale (VRS) was used to quantify pain intensity and unpleasantness. One group was investigated during painful infusion of an acidified phosphate buffer (pH 5.2) into either muscle or skin for 30 minutes. Muscle and skin infusions were adjusted to achieve pain intensity rating of VRS = 40. The second group received sham stimulation of muscle and skin by infusion of non-acidified phosphate buffer (pH 7.3 to 7.4, pain intensity = 0). The third group underwent only one PET scan without sensory stimulation. RESULTS: Unpleasantness ratings were higher (VRS 38.3 vs 25.5) during IM compared to intracutaneous stimulation, despite the same pain intensity (VRS = 40). Sham stimulation revealed no pain or unpleasantness. Regional cerebral glucose metabolism during sham stimulation showed similar findings for intracutaneous and IM infusions with significant activations of the bilateral anterior cingulate, bilateral frontal (premotor) cortex, and the ipsilateral parietal operculum. The comparison of pain vs sham stimulation revealed activations of the bilateral insula for IM but not intracutaneous stimulation. The unpleasantness perception in skin and muscle stimulation was positively correlated to the bilateral insular metabolism. CONCLUSION: The data suggest that the insula represents one main structure where the unpleasantness of tonic pain perception is encoded.

Acids↗
PubMed2005

Follow-up of advanced diabetic neuropathy: useful variables and possible pitfalls.

BACKGROUND: The course of advanced diabetic neuropathy (DN) is largely unknown. AIM: To find variables allowing the follow-up of late stages of DN. METHODS: Thirty diabetic patients with DN were observed. Patients were examined at intervals of 6 months over a period of 2 years. The compound muscle action potentials (CMAPs) were recorded in extensor digitorum brevis (EDB) and flexor hallucis brevis (FHB) muscles. Clinical severity of DN, nerve conduction studies (NCS), quantitative sensory testing (QST) and heart rate variability (HRV) were evaluated. The data were compared with age- and sex-matched controls. RESULTS: All measures were sensitive to the detection of DN. Significant deterioration during follow-up was exclusively found in CMAP analysis of the EDB (p<0.05) and FHB muscles (p<0.03). NCS, QST and HRV remained unchanged within the 2 years of observation. Coincidental changes might occur, if only two time points are chosen for followup. CONCLUSION: Our results indicate that ongoing axonopathy predominates in advanced DN. Repeated testing helps to minimize the impact of coincidental or chance changes in DN follow-up studies.

Action Potentials↗
PubMed2005

Deep pain thresholds in the distal limbs of healthy human subjects.

Pressure pain thresholds (PPTs) in distal limbs have been under-investigated despite their potential clinical importance. Therefore, we compared PPTs over nail bed, bony prominences, and muscle in distal parts of upper and lower limbs. We investigated 12 healthy subjects using three handheld devices: a spring-loaded, analogue pressure threshold meter (PTM) with two operating ranges, and an electronic Algometer. PPTs were determined with three series of ascending stimulus intensities with a ramp of about 50 kPa/s. PPTs were normally distributed in logarithmic space. PPTs over different tissues varied significantly (ANOVA, p<0.001): mean thresholds and 95% confidence intervals were 615 kPa (266-1424 kPa) over the nail bed, 581 kPa (271-1245 kPa) over bony prominences, and 520 kPa (246-1100 kPa) over muscles. PPTs on the foot were higher than on the hand (ANOVA, p<0.01), except over muscles. PPTs were significantly lower with the Algometer than with PTMs (ANOVA, p<0.01); again these differences were least when testing over muscle. There was no significant right-left difference (ANOVA, p=0.33). In spite of considerable variability across subjects, reproducibility within subjects was high (correlation coefficients>0.90). For within-subject comparisons, threshold elevations beyond 33-43% would be abnormal (95% confidence intervals), whereas only deviations from the group mean by at least a factor of two would be abnormal with respect to absolute normative values. PPTs over distal muscles were comparable to published values on proximal limb and trunk muscles. These findings suggest that pressure pain testing over distal muscles may be a sensitive test for deep pain sensitivity and that the simple and less expensive devices are sufficient for testing this tissue type. Intra-individual site-to-site comparisons will be more sensitive than absolute normative values.

Adult↗
PubMed2004

Different short-term modulation of cortical motor output to distal and proximal upper-limb muscles during painful sensory nerve stimulation.

The pattern of upper-limb muscle activation following painful stimulation has not been clarified in detail. We investigated the short-term inhibitory and excitatory effects of painful electrical digital stimulation on the motoneuron pools of distal and proximal upper-limb muscles. Transcranial magnetic stimulation (TMS) was used as test stimulus, and painful digital nerve stimulation as conditioning stimulus for motor evoked potential (MEP) recordings over the abductor digiti minimi (ADM), abductor pollicis brevis (APB), biceps brachii (BB), and deltoid muscles. Inhibition of the conditioned MEP response was most prominent in the distal muscles, whereas BB and deltoid muscles were only weakly inhibited. The mean MEP response over APB decreased with painful cutaneous stimuli, showing maximum inhibition (by 82%) at interstimulus intervals (ISIs) of 50 ms. Inhibition in the ADM was maximal (49%) but less pronounced at an ISI of 40 ms. The BB and deltoid muscles showed inhibition by 25% and 29%, respectively. Significant facilitation was present in BB and deltoid muscles by 43% and 41% at an ISI of 100 ms, but not in the smaller hand muscles. The observed pattern of upper-limb muscle activation corresponds to the protective withdrawal reflex and the neuronal basis of the observed short-term modulation of motor activity is compatible with a spinal or brainstem pathway.

Adult↗
PubMed2004

Effects of botulinum toxin type A on vibration induced facilitation of motor evoked potentials in spasmodic torticollis.

BACKGROUND AND AIMS: It has not been clarified if botulinum toxin (BTX) injection leads to muscle spindle dysfunction in man. This study aimed to test the hypothesis that BTX application reduces the facilitation of a magnetic evoked response (MEP). METHODS: We used the vibration induced facilitation of an MEP of the sternocleidomastoid muscle (SCM) as a surrogate marker for muscle spindle function in 20 healthy subjects and 10 patients with idiopathic rotational torticollis in whom BTX was injected unilaterally. RESULTS: The increase in the amplitude and area of the MEPs in the clinically not affected and untreated SCM of the patients did not differ significantly from the controls. At baseline, the vibration induced increase in the affected SCM of the patients was significantly lower than in the control group. Six weeks after BTX application, the observed facilitation decreased significantly (amplitude and area: p<0.001) when compared with baseline values. Twelve weeks after BTX application, facilitation showed an increase in the values of the amplitude (p<0.001), but not of the area when compared with the six week examination. CONCLUSIONS: We demonstrated that the vibration induced MEP facilitation in the SCM of patients with torticollis significantly decreased six weeks after BTX application and again increased after 12 weeks in part when looking at MEP amplitude. This observation is suggestive of denervation and reinnervation of the muscle spindles after BTX injection.

Adult↗