Evidence of specific cognitive deficits in patients with chronic low back pain under long-term substitution treatment of opioids.

BACKGROUND: There is a growing number of patients worldwide being treated with long-term opioids for chronic non-cancer pain, although there is limited evidence for their effectiveness in improving pain and function. Opioid-use related adverse effects, especially in cognitive functioning in these patients, are rarely evaluated. OBJECTIVES: The present study investigated the cognitive functions of patients with chronic back pain who underwent long-term opioid treatment in comparison with those patients without opioid usage and healthy controls. STUDY DESIGN: A prospective, nonrandomized, cross-sectional study. SETTING: Multidisciplinary pain management clinic, specialty referral center, University Hospital in Germany. METHODS: In a prospective cross-sectional design, 37 patients with chronic back pain who underwent long-term opioid therapy (OP) were compared with 33 patients with chronic back pain without opioid therapy (NO) and 25 healthy controls (HC). Assessment of primary outcome included cognitive function such as information processing speed, choice reaction time, pattern recognition memory, and executive function. Other data included pain, back function, depression and anxiety, use of medication, and education status. The relationship between cognitive functions and anxiety/depression was analysed. RESULTS: Both patient groups needed significantly longer time in information processing when compared to HC (Group 1: 41.87 ± 20.47 Group 2: 38.29 ± 19.99 Group 3: 30.25 ± 14.19). Additionally, OP patients had significantly reduced spatial memory capacity, flexibility for concept change, and impaired performance in working memory assessment compared to NO patients and HC. The impaired cognitive outcomes were significantly associated with pain intensity, depression scores, and medication use. LIMITATIONS: Limitations include small number of patients with heterogeneous opioid therapy and the nonrandomized observational nature of the study. CONCLUSIONS: Our findings give a differential view into the cognitive changes from chronic back pain with and without long-term opioids treatment. Chronic back pain itself impairs some distinct cognitive functions. Long-term opioid therapy adds further cognitive impairment.

Individual analysis of EEG background-activity within school age: impact of age and sex within a longitudinal data set.

OBJECTIVES: Quantitative EEG can monitor changes in brain function during development and may help to understand developmental disorders. However, current EEG-databases are primarily based on standardized frequency bands which disregard age-related changes in alpha peak frequency (PF) and therefore complicate the interpretation of spectral estimates in the theta and alpha range. METHODS: We used a two point longitudinal design in order to analyze intraindividual changes in 40 healthy children and adolescents with age (T1: 6-18 years; interval approximately 4 years). Using a 64-channel eyes closed resting EEG we calculated absolute/relative power in individualized frequency bands (IFB: delta, theta, alpha1/2 and beta) based on PF. RESULTS: PF increased with age, with changes being larger for children than adolescents. Controlling for changes in PF, changes in absolute/relative alpha1/2 power and in absolute beta power were minor. Relative beta power, however, increased while absolute/relative delta and theta power decreased massively. Sex-differences in PF did not reach significance. However, boys exhibited larger changes during adolescence than girls for all absolute power measures except alpha. CONCLUSION: Normal EEG development during school-age is mainly based on an absolute decrease of slow frequency activity and increases of PF which may be interpreted in terms of a reorganization of the EEG towards a higher frequency oscillatory scale rather than a maturation of the theta-alpha1/2 band power sequence. Age-related changes differed between boys and girls suggesting a different developmental timing for the sexes. In future studies a combined analysis of PF and IFB may help to specify deviations in developmental disorders.

Olfactory impairment in monozygotic twins discordant for schizophrenia.

OBJECTIVE: Several studies demonstrated olfactory dysfunction in patients with schizophrenia, some reported deficient olfaction in unaffected relatives of schizophrenics as well. This study differentially assessed olfactory acuity as well as smell identification and smell discrimination in monozygotic twins discordant for schizophrenia and healthy, monozygotic control twins, to determine the genetic basis of different olfactory modalities and their association to schizophrenia. METHOD: The Sniffin'Sticks test,a comprehensive and standardized olfactory test, was employed to assess the olfactory function of 10 monozygotic twin pairs discordant for schizophrenia versus 10 age- and sexmatched healthy,monozygotic twin pairs. RESULTS: Olfaction of affected monozygotic twins was globally impaired. Partial olfactory impairment of their unaffected co-twins may point to a genetic cause of olfactory impairment in schizophrenia. The influence of genetic factors was most evident for olfactory acuity and least evident for smell identification. All olfactory functions declined with duration of illness. Side of stimulus presentation did not influence olfactory performance. CONCLUSIONS: Genetic factors associated with olfactory dysfunction may contribute to schizophrenia. The degree of the genetic influence on olfaction depends on the olfactory domain under examination.

Pattern-reversal visual-evoked potentials in children with migraine and other primary headache: evidence for maturation disorder?

Recently, evidence for a disturbed maturation of cerebral information processing in migraine came from studies investigating the auditory-evoked contingent negative variation and the auditory-evoked potential from childhood to adulthood. This study is to clarify whether age-dependent development is altered also for the processing of visual stimuli in migraine. Components of pattern-reversal visual-evoked potentials at four different spatial frequencies (which can preferentially activate the magno- and the parvocellular visual system) were compared between children aged 6 and 18 years with primary headache (N = 123; 67 migraine without aura, MO; 32 migraine with aura, MA; 24 tension-type headache, TH) in the headache-free interval and healthy controls (N = 82). Children were divided into two age groups: 6-11 years (pre- and early puberty) and 12-18 years (late and post-puberty). Age-dependent development was normal for N80 and P100 latency in children with primary headache, but altered for N135 latency as indicated by a significant interaction among the factors diagnosis, spatial frequency and age group (P < 0.01). In headache-free controls, N135 latency reduction between pre- and post-puberty age was most pronounced at high spatial frequency. The main 'decline' of N135 latency with increasing age was shifted to lower spatial frequencies in the headache subgroups. The results give evidence that maturation of visual processing is partly disturbed in migraineurs.

[Changes in test norms of spelling achievement and nonverbal intelligence]. / Normverschiebungen bei Rechtschreibleistung und sprachfreier Intelligenz.

The norms of the spelling test R-T Form C "Moselfahrt" (Althoff et al. 1974) from the year 1968 and of the nonverbal intelligence test CFT 20 (form A/part 1) from the year 1977 (Weiss 1987) are evaluated for their actual validity. In 1995, both original tests were being administered to an epidemiological sample (N = 592) of adolescents and young adults in the age of 16 to 30 years having passed at least their obligatory amount of school years. These results are being compared to those of the original norm samples. Using the norms for the CFT 20 from 1977 adolescents and young adults achieve in the year 1995 a mean IQ of 110.8 points, equaling a yearly IQ-gain of 0.6 IQ-points. This exceeds the expected gain of 0.33 IQ-points annually according to the literature and indicates a distinct change of norms. There were no significant gender differences found. The distribution of mistakes in the spelling test R-T "Moselfahrt" compared to the original norm sample from 1968 changes considerably as well and requires revised test norms. With an increase from 9-11 mistakes (depending on the age norm) to 19.8 mistakes the mean amount of mistakes is almost being doubled. Extremely high numbers of mistakes occurred more frequent and could not be differentiated according to the old norms. Using the original norms from 1968 in the year of 1995 12.4% of the sample achieve with a T-score of 20 the lower limit of the measured value scale and the overall mean has decreased by 1.2 standard deviations to T-score = 38.48% of the sample reach a result that equates percentage 10 or less which is interpreted as insufficient school mark. Women's mean spelling achievement is significantly better than men's. Causes and implications of this scissors-like development of deteriorated spelling achievement and increased nonverbal intelligence are being discussed. Tables containing the new standardization scores are included in the appendix.