Markus M. Schugens

Classical conditioning after cerebellar lesions in humans

We explored classical conditioning in human subjects who had lesions in their cerebellar circuitry. Seven patients with damage to cerebellar structures and matched control subjects underwent simple delay tone-airpuff conditioning. Eyelid conditioned response (CR) acquisition was severely disrupted in the patient group, whereas autonomic CRs and slow cortical potentials developing between conditioned stimulus (CS) and the unconditioned stimulus (UCS) were unaffected. Results are consistent with animal studies and earlier case reports indicating that intact cerebellar structures are necessary for the acquisition of classically conditioned motor responses.

The cerebellum and cognitive functions in humans

Recent neuropsychological studies have given rise to the hypothesis that the cerebellum is involved in nonmotor cognitive functions. The interpretation of these findings is, however, restricted by methodological problems, such as heterogenous patient samples. The present study compared patients with pathology confined to the cerebellum and patients with combined cerebellar and brainstem lesions to matched normal controls on a range of memory and learning tasks. Two procedural learning tasks were also conducted, involving perceptual (mirror reading) and conceptual skill acquisition (the Tower of Hanoi task). Patients with damage to both cerebellum and brainstem, but not patients with cerebellar pathology alone, showed impairments on memory and visuoconstructive tasks and evidence of frontal lobe dysfunction. Cerebellar damage had no effect on skill acquisition. These results do not support the hypothesis of cerebellar involvement in procedural learning per se.

Zur Anwendbarkeit des West Haven-Yale Multidimensional Pain Inventory im deutschen Sprachraum

The reliability and validity of a German version (MPI-D) of the West Haven-Yale Multidimensional Pain Inventory (WHYMPI) was assessed in a sample of 185 chronic pain patients. MPI-D shows high internal consistency, valid subscales, and a factor structure that is comparable to the American version. The Interference scale of part 1 includes an additional item and one other item was excluded; the Life Control scale had one item added. In section 2, one item was dropped, and in section 3 only 3 instead of 4 activity scales were found. The questionnaire is sensitive to therapeutic change. The German scale means are lower for the scales indicating more disturbance or severity and higher for the scales indicating less disturbance. It is not clear whether this reduced pain impact is characteristic of German pain patients in general, or whether it is due to the less severely affected sample tested in this study.The reliability and validity of a German version (MPI-D) of the West Haven-Yale Multidimensional Pain Inventory (WHYMPI) was assessed in a sample of 185 chronic pain patients. MPI-D shows high internal consistency, valid subscales, and a factor structure that is comparable to the American version. The Interference scale of part 1 includes an additional item and one other item was excluded; the Life Control scale had one item added. In section 2, one item was dropped, and in section 3 only 3 instead of 4 activity scales were found. The questionnaire is sensitive to therapeutic change. The German scale means are lower for the scales indicating more disturbance or severity and higher for the scales indicating less disturbance. It is not clear whether this reduced pain impact is characteristic of German pain patients in general, or whether it is due to the less severely affected sample tested in this study.ZusammenfassungEine deutsche Fassung des West Haven-Yale Multidimensional Pain Inventory (WHYMPI) wird vorgestellt, die an einer Stichprobe von 185 Schmerzpatienten auf ihre Reliabilität und Validität überprüft wurde. Der Bogen erfaßt in 12 Skalen psychosoziale Aspekte chronischer Schmerzen: Schmerzstärke, Beeinträchtigung durch den Schmerz, affektive Verstimmung, Lebenskontrolle, soziale Unterstützung, strafende, zuwendende und ablenkende Reaktionen einer Bezugsperson sowie Aktivitäten im Haus, außer Haus, im sozialen und im Freizeitbereich sowie ein allgemeines Aktivitätsniveau. Der MPI-D erwies sich als intern konsistentes Maß, dessen Faktorenstruktur weitgehend der englischsprachigen entspricht und dessen Unterskalen als valide anzusehen sind. Der Bogen ist darüber hinaus änderungssensitiv, was ihn als Therapieerfolgsmaß einsetzbar macht. Im Vergleich zur US-amerikanischen Stichprobe stellten sich die deutschen Patienten als weniger beeinträchtigt dar, was an der spezifischen Stichprobe oder aber an kulturellen Unterschieden liegen mag.

[The applicability of the West Haven-Yale multidimensional pain inventory in German-speaking countries. Data on the reliability and validity of the MPI-D.].

The reliability and validity of a German version (MPI-D) of the West Haven-Yale Multidimensional Pain Inventory (WHYMPI) was assessed in a sample of 185 chronic pain patients. MPI-D shows high internal consistency, valid subscales, and a factor structure that is comparable to the American version. The Interference scale of part 1 includes an additional item and one other item was excluded; the Life Control scale had one item added. In section 2, one item was dropped, and in section 3 only 3 instead of 4 activity scales were found. The questionnaire is sensitive to therapeutic change. The German scale means are lower for the scales indicating more disturbance or severity and higher for the scales indicating less disturbance. It is not clear whether this reduced pain impact is characteristic of German pain patients in general, or whether it is due to the less severely affected sample tested in this study.The reliability and validity of a German version (MPI-D) of the West Haven-Yale Multidimensional Pain Inventory (WHYMPI) was assessed in a sample of 185 chronic pain patients. MPI-D shows high internal consistency, valid subscales, and a factor structure that is comparable to the American version. The Interference scale of part 1 includes an additional item and one other item was excluded; the Life Control scale had one item added. In section 2, one item was dropped, and in section 3 only 3 instead of 4 activity scales were found. The questionnaire is sensitive to therapeutic change. The German scale means are lower for the scales indicating more disturbance or severity and higher for the scales indicating less disturbance. It is not clear whether this reduced pain impact is characteristic of German pain patients in general, or whether it is due to the less severely affected sample tested in this study.ZusammenfassungEine deutsche Fassung des West Haven-Yale Multidimensional Pain Inventory (WHYMPI) wird vorgestellt, die an einer Stichprobe von 185 Schmerzpatienten auf ihre Reliabilität und Validität überprüft wurde. Der Bogen erfaßt in 12 Skalen psychosoziale Aspekte chronischer Schmerzen: Schmerzstärke, Beeinträchtigung durch den Schmerz, affektive Verstimmung, Lebenskontrolle, soziale Unterstützung, strafende, zuwendende und ablenkende Reaktionen einer Bezugsperson sowie Aktivitäten im Haus, außer Haus, im sozialen und im Freizeitbereich sowie ein allgemeines Aktivitätsniveau. Der MPI-D erwies sich als intern konsistentes Maß, dessen Faktorenstruktur weitgehend der englischsprachigen entspricht und dessen Unterskalen als valide anzusehen sind. Der Bogen ist darüber hinaus änderungssensitiv, was ihn als Therapieerfolgsmaß einsetzbar macht. Im Vergleich zur US-amerikanischen Stichprobe stellten sich die deutschen Patienten als weniger beeinträchtigt dar, was an der spezifischen Stichprobe oder aber an kulturellen Unterschieden liegen mag.

Memory and Skill Acquisition in Parkinson's Disease and Frontal Lobe Dysfunction

Animal experiments and human neuropsychological studies have provided evidence for the hypothesis that skill acquisition may be regulated by the basal ganglia. In the present studies, perceptual and cognitive skill acquisition as well as a number of explicit verbal memory functions were investigated in patients in early and more advanced stages of Parkinsons disease (PD) and in patients with frontal lobe lesions. Patients in more advanced stages of PD were impaired at cognitive skill acquisition as well as during recall conditions that involved active semantic organisation of the stimulus material. Similar explicit memory deficits were present in frontally lesioned patients. PD patients with unilateral symptoms showed a selective impairment in acquiring a cognitive skill. Perceptual skill acquisition was preserved in all groups. The overall pattern of memory impairment in PD is largely consistent with dysfunction of fronto-striatal circuitry.

The NMDA antagonist memantine impairs classical eyeblink conditioning in humans

The present study investigated the effects of a single oral dose (30 mg) of the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist memantine on memory and learning in human subjects. Sixteen male healthy volunteers participated in a double blind placebo controlled study. There were no significant effects of memantine on mood, attention or immediate and delayed verbal and visuospatial memory. Memantine did, however, delay the acquisition of classical eyeblink conditioning and reduced the overall frequency of conditioned responses without affecting reflex or spontaneous eyeblinks. These findings are compatible with the higher affinity of memantine to cerebellar as compared to forebrain tissue and demonstrate the dissociability of different memory systems by pharmacological tools.

Memory dysfunction of the frontal type in normal ageing.

In this study healthy subjects divided into five consecutive age groups (20-60 years of age) completed a series of memory tasks which had previously been shown to reveal impairments in patients with frontal lobe lesions. Significant age differences were found for free recall, retention rates for material which required effortful encoding, memory for temporal order and prospective memory. In the tests addressing these memory functions, subjects of more than 60 years of age performed more poorly than the youngest group, and they also showed evidence of false recognition (increased false alarm rates and confabulatory responses). The general pattern suggests that inefficient frontal functioning might contribute to age-related memory problems.

Discrimination of muscle tension in chronic pain patients and healthy controls

The purpose of this study was to assess the perception of muscle tension in chronic pain patients and healthy controls. Twenty chronic back pain patients, 20 patients who suffered from temporomandibular pain and dysfunction, and 20 healthy controls were instructed to produce eight different levels of muscle contraction in either the m. masseter or the m. erector spinae. Each level was produced three times; trials were presented in random order. Analyses of the accuracy and the sensitivity of discrimination of muscle tension levels revealed that the patients were less able to perceive muscle contraction levels correctly and that they underestimated their actual levels of muscle tension. Patients and controls did not differ in the extent to which they contracted muscles not involved in the task. Patients suffering from musculoskeletal disorders seem to display a genuine deficit in discrimination of muscle tension that is related to neither local physiological changes at the site of pain, lack of motivation, inattention, nor fatigue.

T-Maze Discrimination and Reversal Learning After Unilateral Temporal or Frontal Lobe Lesions in Man

The interpretation of conditional discrimination and reversal learning as acquisition of declarative knowledge suggests that subjects with temporal lobe/hippocampal lesions are likely to be impaired on such tasks. Patients with unilateral left or right temporal lobectomy (and small hippocampal excisions) and patients with unilateral frontal lobe resections were compared with healthy controls on a discrimination reversal task, embedded in a computer game modelled on T-maze tasks traditionally used in animal experiments. The right temporal group showed a deficit in acquiring an initial conditional discrimination, and the frontal group tended to display a marginal impairment in discrimination reversal. These findings are compared with results from animal studies in terms of the mechanisms underlying reversal learning.

Differential effects of aging on explicit and implicit memory

Abstract In the present study, five consecutive age groups ranging from the 20s to the 60s were compared on a range of explicit and implicit memory tests which were modelled on the clinical tasks used to assess amnesia. With respect to explicit memory, the ability to recall verbal or visual material was seen to decline steadily with increasing age at immediate and delayed testing; there were, however, no consistent age differences regarding performance on recognition tasks. Perceptual skill acquisition within the context of a mirror reading task was unaffected by age, while word stem completion priming tended to decline across the age groups. Factor analysis revealed three factors: verbal explicit memory, visual memory (comprising visual recall and stem completion priming), and skill acquisition. the present findings indicate dissociable effects of normal aging on explicit and implicit memory, and thereby some degree of qualitative resemblance to human amnesia.