Complex Motor Function in Humans: Validating and Extending the Postulates of Alexandr R. Luria

Distinctive features of bimanual coordination in idiopathic normal pressure hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by cerebrospinal fluid circulation disorders, and presents as gait and balance disturbances similar to those observed in other incurable neurological diseases. Although previous studies have reported deficits in bimanual coordination among patients with iNPH, these potential pathological characteristics have not received much attention to date. This study investigated the temporal characteristics of a bimanual finger-tapping task in patients with iNPH, focusing on within- and between-hand coordination.

METHODS

Study participants comprised three groups: patients with iNPH (N = 19, mean age = 76.9 ± 5.6 years), older adults (N = 19, 76.4 ± 5.3 years), and younger adults (N = 13, 32.2 ± 8.5 years). Participants performed a bimanual finger-tapping task under five conditions that manipulated the temporal differences between the two taps.

RESULTS

The iNPH group exhibited significantly greater errors in both within- and between-hand coordination tasks compared to the other two groups.

CONCLUSION

These results suggest that assessing temporal errors in bimanual coordination tasks, particularly within-hand coordination, may be useful for uncovering pathological characteristics specific to iNPH.

Neuropsychological aspects of 10-year-old children

OBJECTIVE: To characterize neuropsychological aspects of 10-yearold children. METHOD: Out of 30 children, 26 cognitively normal 10-year-old public school students answered tests extracted from Luria-Nebraska Neuropsychological Battery: Children's Revision. The study was transversal. Descriptive and inferential statistical analysis were carried out. RESULTS: Most of the 10-year-old children retold a story (69.2%), understood it making correct inference (84.6%) and reproduced it adequately in writing (76.9%) - 14.9% was the average number of incorrectly written words and 0.179 was the errors per written word coefficient. Besides, 53.8% showed logical thought process and 73.1% had a correct notion of "x more than...". They got five out of eight in the visuo-spatial test, an intermediary result. These results show that the tertiary areas of units II and III are developed in most 10-year-old children. The most frequent types of written mistakes were: oral influence (26.3%), multiple representation (22.5%) and omission (18.4%). As to coding principles, the mostly uncomplied with rule was vowel nasalization at end of syllable (23,53%). CONCLUSIONS: Ten-year-old children in the studied population understood and reproduced a story orally and in writing with a low coefficient error/word. The majority completed the visuospatial tests and presented logical thought process. When "x more than..." notion is absent it may be an indicator that all is not well in the reading/writing process.

Cognitive disturbances in primary blepharospasm

The common belief that primary dystonia is a purely motor disorder with no anatomical substrate and no other accompanying neurological dysfunction has recently been challenged. In addition, there is increasing evidence that the basal ganglia besides motor control, plays a role in cognitive functioning. However, no systematic cognitive performance evaluation has been carried out in patients with primary blepharospasm (BS), one of the most common forms of adult dystonia. We evaluated a series of 20 patients with primary BS and a group of 17 controls matched by severity of mood symptoms, age, and sex. BS patients performed significantly worse on the Luria sequencing test, Purdue pegboard test, reciprocal coordination, tactile denomination, and reverse visuospatial span and the differences persisted after correction for age, duration of disease, severity of BS, and degree of depression. The Wisconsin card sorting test showed no statistical difference, but BS patients made more errors and more perseverative answers than expected according to population means, whereas the control group performed poorly but within normal parameters. Our findings suggest broad cortical involvement in focal dystonia that is not correlated with the severity or duration of dystonia.

A review and empirical study of the composite scales of the Das-Naglieri cognitive assessment system

Alexander Luria’s model of the working brain consisting of three functional units was formulated through the examination of hundreds of focal brain-injury patients. Several psychometric instruments based on Luria’s syndrome analysis and accompanying qualitative tasks have been developed since the 1970s. In the mid-1970s, JP Das and colleagues defined a specific cognitive processes model based directly on Luria’s two coding units termed simultaneous and successive by studying diverse cross-cultural, ability, and socioeconomic strata. The cognitive assessment system is based on the PASS model of cognitive processes and consists of four composite scales of Planning–Attention–Simultaneous–Successive (PASS) devised by Naglieri and Das in 1997. Das and colleagues developed the two new scales of planning and attention to more closely model Luria’s theory of higher cortical functions. In this paper a theoretical review of Luria’s theory, Das and colleagues elaboration of Luria’s model, and the neural correlates of PASS composite scales based on extant studies is summarized. A brief empirical study of the neuropsychological specificity of the PASS composite scales in a sample of 33 focal cortical stroke patients using cluster analysis is then discussed. Planning and simultaneous were sensitive to right hemisphere lesions. These findings were integrated with recent functional neuroimaging studies of PASS scales. In sum it was found that simultaneous is strongly dependent on dual bilateral occipitoparietal interhemispheric coordination whereas successive demonstrated left frontotemporal specificity with some evidence of interhemispheric coordination across the prefrontal cortex. Hence, support for the validity of the PASS composite scales was found as well as for the axiom of the independence of code content from code type originally specified in 1994 by Das, Naglieri, and Kirby.

Neural correlates of pre-performance routines in expert and novice archers

The objective of the present study was to determine differences in neural networks between expert and novice archers during an archery pre-performance routine period (PPR). The experiment was conducted with eight world-class competitor or Olympic medalist archers and eight novices. In the experiment, the task was to shoot (by clicking a mouse with the right hand) if an archery target appeared on an LCD embedded in an functional magnetic resonance imaging (fMRI) scanner. The resultant fMRI data showed that when the experts were aiming, the occipital gyrus and temporal gyrus were activated, but when the novices were aiming, the frontal area was mainly activated. In addition, the anterior cingulate and posterior cingulate gyrus of the limbic lobe were also activated in the expert and novice groups, respectively. Our results demonstrated that expert and novice archers differed in levels of brain activation during the PPR period of a simulated archery task.

Network activation during bimanual movements in humans

The coordination of movement between the upper limbs is a function highly distributed across the animal kingdom. How the central nervous system generates such bilateral, synchronous movements, and how this differs from the generation of unilateral movements, remain uncertain. Electrophysiologic and functional imaging studies support that the activity of many brain regions during bimanual and unimanual movement is quite similar. Thus, the same brain regions (and indeed the same neurons) respond similarly during unimanual and bimanual movements as measured by electrophysiological responses. How then are different motor behaviors generated? To address this question, we studied unimanual and bimanual movements using fMRI and constructed networks of activation using Structural Equation Modeling (SEM). Our results suggest that (1) the dominant hemisphere appears to initiate activity responsible for bimanual movement; (2) activation during bimanual movement does not reflect the sum of right and left unimanual activation; (3) production of unimanual movement involves a network that is distinct from, and not a mirror of, the network for contralateral unimanual movement; and (4) using SEM, it is possible to obtain robust group networks representative of a population and to identify individual networks which can be used to detect subtle differences both between subjects as well as within a single subject over time. In summary, these results highlight a differential role for the dominant and non-dominant hemispheres during bimanual movements, further elaborating the concept of handedness and dominance. This knowledge increases our understanding of cortical motor physiology in health and after neurological damage.

Disruption of reciprocal coordination by a medial frontal stroke sparing the corpus callosum

Aleksandr Luria described several tests of higher motor function, including the "reciprocal coordination" test of bimanual coordination. Although these tests are commonly used to assess frontal lobe function, their specific neuroanatomic underpinnings are not completely understood. We describe a man with a medial frontal stroke sparing the corpus callosum with a defect in Luria's reciprocal coordination test but otherwise intact motor abilities, including other tests of higher motor function.

The mind of expert motor performance is cool and focused

Extraordinary motor skills required for expert athletic or music performance require longstanding and intensive practice leading to two critical skills, a level of maximal performance that far exceeds that of non-experts and a degree of privileged focus on motor performance that excludes intrusions. This study of motor planning in expert golfers demonstrated their brain activation during their pre-shot routine to be radically different than in novices. The posterior cingulate, the amygdala-forebrain complex, and the basal ganglia were active only in novices, whereas experts had activation primarily in the superior parietal lobule, the dorsal lateral premotor area, and the occipital area. The fact that these differences are apparent before the golfer swings the club suggests that the disparity between the quality of the performance of novice and expert golfers lies at the level of the organization of neural networks during motor planning. In particular, we suggest that extensive practice over a long period of time leads experts to develop a focused and efficient organization of task-related neural networks, whereas novices have difficulty filtering out irrelevant information.