Cognitive and Communicative Perspectives on Physiotherapy: a Review

Advances in Physiotherapy 1999; 1:37 – 44

REVIEW ARTICLE

Cognitive and Communicative Perspectives on Physiotherapy: a Review JERKER RO8 NNBERG Department of Education and Psychology, Linko¨ping University, Sweden

Abstract In this paper, the area of cognition and communication is reviewed with special emphasis on the role of motor functions in cognition and communication, and their relation to physiotherapy. Short and long-term cognitive consequences caused by motor activity or by neuromotor disorders are addressed, as well as the motor-cognitive prerequisites for language and (alternative) communica-

tion. The working memory notion is useful in summarizing similarities among the many neuro-motor disorders reviewed. It is commonplace that executive, central functions (e.g., attention) are negatively affected. In addition, phonology is a key function in the understanding of working memory support for alternative communication. It is ventured that this type of theoretical analysis of consequences and prerequisites is important for the further devel-

INTRODUCTION Traditionally, physiotherapy research has focused on motor activity, how it can be measured and assessed, and under what conditions motor capabilities can improve. Very little physiotherapy research has been carried out that addresses either the cognitive consequences of motor activity or the necessary motorcognitive prerequisites for communication, which this review suggests could be both practically and theoretically important in order to advance physiotherapy research. The purpose of this review article is therefore to argue that more research needs to be devoted to certain integrative aspects of physiotherapy, taking into account the cognitive and communicative aspect of a disabled or injured individual. These aspects are by no means exhaustive, but can broaden the perspective on physiotherapy in significant ways and also provide important insights into various forms of assessment and treatment procedures. One theoretical link that needs to be explored is the putative relation between cognition, action, and communication. Generally speaking, the approach to view the individual as acting in, and inter-acting with the physical and social environment has received increased research attention throughout recent © 1999

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opment of physiotherapy in research and practice. KEY WORDS: Alzheimer – attentiondeficit-hyperactivity-disorder – central auditory nervous system – cerebral palsy – cognition – motor activity – multiple sclerosis – Parkinson – phonology – physiotherapy – sign language – spoken language – working memory.

decades among cognitive behavioural scientists. The view that cognitive functions such as working memory, attention, inference-making are not isolated from the overarching communicative needs of the individual invites the proposal that cognition is embedded in – and sometimes a prerequisite for – communication and action (1). In this article I explore the typically cross-disciplinary research which can be relevant to the area of cognition-action-communication, with the assumption that such links are important for the understanding of physiotherapeutic models and assessment procedures. To this end, the research examples cited will draw heavily on cognitive and linguistic neuroscience research in different patient groups.

COGNITION, ACTION AND COMMUNICATION Cognitive psychology has been successful in applying some of its conceptual repertoire to the domain of communication, communication psychology, and communicative disability. There are now many books and journal issues on cognitive aspects of speech (2), speechreading (3–5), reading (6), writing (7), applications to brain injury (8), communicative disability (9,10), as well as to cognition and action in applied real-life settings (1, 11–13). 37

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One important feature of the area of cognition and communication is its focus on the necessity of certain cognitive abilities/functions for carrying out certain communicative acts, or for compensation by means of new, alternative communicative forms. Quite often cognitive prerequisites have been related to the ability to use communicative prostheses or sensory aids. The area typically utilizes a multitude of neuroscience and cognitive-perceptual approaches (10, 14). Another feature of the area is the study of disabling cognitive or communicative consequences of sensory impairment (15 – 17) or central disorders such as central auditory processing deficit (CAPD) or attentional deficit hyperactivity disorder (ADHD) (18, 19). Both sensory and central aspects of cognitive functions represent important means by which to gain knowledge of assessment purposes, but also for setting up compensatory communicative treatment programmes.

COGNITIVE-BEHAVIOURAL TREATMENT APPROACHES IN PHYSIOTHERAPY Cognitive examples that have obvious connections to physiotherapy are those which focus on various types of relations between motor activities, cognition, and communication. This link is important, as it has a bearing on cognitive-behavioural movement-retraining programmes (20), cognitive components in rehabilitation (21), or on the importance of cognitive predictors of rehabilitation outcome after stroke (22). Further examples concern the integration of physical therapy with cognitive-behavioural techniques as related to pain (23, 24). Common techniques in this context are relaxation and operant activity training (25). Physiotherapeutic treatment of vertigo also needs to take psychological factors into account (26). More explicit research concerning the relation between cognitive activities and balance functions has been carried out by Andersson et al. (27) with the aim of studying tasks consuming central information-processing resources. This research is in its infant stages, but will hopefully have clinical consequences for assessment of patients who are particularly prone to react with destabilization in the face of concurrent information load. 38

Advances in Physiotherapy 1 (1999)

What is common to the above examples is that they obviously focus on motor functions of different kinds and psychological/cognitive factors in a relatively general sense. However, they do not explicitly address either the cognitive prerequisites for motor function or improvement, or the cognitive or communicative consequences of certain motor capabilities. The wider context of addressing cognition as a prerequisite or as a consequence may turn out to represent an important step for the development of physiotherapeutic models and theory. Both these features are delineated below.

MOTOR ACTIVITY, COGNITION AND COMMUNICATION Motor memory: short-term consequences Many studies in the area of cognitive psychology have focused on the relation between motor activity and memory function. It is important to understand memory function – seen as an integral part of human cognition and language function – in order to promote improvements in assessments, management, and perhaps also for the long-term treatment outcome. However, the examples referred to below concern short-term cognitive consequences. One particularly potent task in this respect was introduced by Cohen (28). It was denoted subjectperformed task (so-called SPT), with the subjects enacting certain imperatives at encoding (e.g., clap your hands; tie your shoe-lace, etc.). During the test the subjects typically are to respond verbally. The main control condition is verbal encoding of ‘‘clap your hands’’. Data show that both recognition and recall of SPTs are boosted for normal individuals, and that for example age differences are eliminated. However, empirical disputes are present with respect to encoding strategies, subject-performed tasks versus experimenter-performed tasks, and levels-ofprocessing effects (29). Due to these and other inconsistences, several hypotheses have been advanced that attempt to explain SPT performance. For example, one explanation by Ba¨ckman & Nilsson seeks an understanding in terms of multimodal and ‘‘rich’’ encoding (30); another argues that SPT-encoding is strategy-free, lacking verbal rehearsal (31), whereas Engelkamp & Zimmer (32) put forward the hypothesis that efficiency of encoding is mediated by the


motor component per se at encoding. Supporting the latter theory, a very recent study (33) has compared event-related brain potentials (ERPs) for recognition performance of SPTs with ERPs following recognition of verbally encoded memory tasks. The interesting feature of the data was that a larger fronto-central negativity was found for the SPTs, suggesting that the advantage of SPT performance is to be associated with motor (re)activation at retrieval. Thus, the motor theory of explanation for the SPT superiority effect is supported (34). Applications of this type of memory research – relevant for physiotherapy research and practice – are plentiful and range from showing reduced age-related deficits with SPTs to the necessity of motor encoding and category-cue retrieval support for patients with Alzheimer’s disease (AD) (35, 36), improved memory for educable mentally retarded (37), and to patient management based on spared motor memory functions in AD (38). And, Parkinson’s disease (PD) patients show recall levels comparable to controls with SPTs (Karlsson, personal communication). What is evident from the above is that the SPT is a task with properties which fulfil compensatory purposes for non-disabled as well as disabled individuals. One challenge is whether the observation that PD patients also can compensate – despite their motor slow down – may open up for motor memory management strategies. Such an empirical possibility definitely belongs to the domain of future collaboration among cognitive scientists and physiotherapists. Another challenge is the potentially useful connection between SPT-learning and language processing. Kormi-Nouri (39) has not emphasized the motor component of SPTs but rather argues that the episodic integration between noun and verb is the crucial feature at encoding (40); this relation is also heavily influenced by pre-experimental, semantic relations between noun and action verb (39). The general consequence of this research is that SPTs may represent a medium by which simple language learning (noun-verb) could be optimized via semantic support; a possibility that may be utilized among language-impaired children who have intact or sufficient motor capacities.

COGNITION, COMMUNICATION AND PHYSIOTHERAPY

Cognitive function: long-term consequences Relative lack of motor activity in the human subject is not always accompanied by cognitive deficits. Although the classical description of PD patients is a general slowing down of motor function, its programming and execution, this does not always manifest itself in cognitive deficits (41). For example, reaction time studies fail to show agreement with respect to a generalized decrease in speed in PD patients, although tasks such as speed in memory scanning are negatively affected. Immediate memory is not particularly impaired, but more complex and retrieval demanding memory tasks consistently show impairment in PD patients. PD patients, as well as patients with related disorders (e.g., Huntington’s disease and Multiple Sclerosis (MS)), also demonstrate impaired, more attentionally complex executive functions (e.g., planning and execution, monitoring and inhibiting functions), visuospatial disturbances, and impaired ability to manipulate information (41). The executive dysfunctions of PD patients may thus explain why more complex memory retrieval tasks tend to exhaust their capacities. Strong evidence suggests that PD is associated with a loss or death of dopaminergic neurons which are part of the cortical-striatal-thalamic-cortical circuit, which in turn is assumed to underlie important executive functions of the brain (42). Other neurological conditions reported to be associated with hyperactivity – in some sense opposite to PD – are those connected with ADHD and potentially also with CAPD (19). As with PD, there is evidence implicating dopaminergic neuronal networks; in this case high concentrations of dopamine are found in boys with ADHD (18). And, prefrontal cortex has been implicated in brain-imaging studies of ADHD children (43), which plays an essential role in the cortical-basal ganglia-cortical circuit. The characteristic hyperactivity or motor unrest demonstrated by ADHD children is parallelled by cognitive inabilities to deal with inhibition and delay of responses (44). Inadequate inhibitory motor control may also be associated with Tourette’s syndrome and obsessive compulsive disorders. Developmental coordination disorders (DCD) may show visual perceptual deficits, but the most typical characteristic is slow movements dependent on a lack of anticipatory 39

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planning of movements (45). Frontal, executive deficits are again implicated. As is the case with PD, executive functions provide a potentially useful and general framework through which ADHD and many motor disorders can be conceptualized. In addition, ADHD and CAPD children overlap in their cognitive and communicative abilities, such that they demonstrate problems with selective attention, poor listening skills and distractibility (19). The story may also be complemented with MS, which essentially is a disorder due to demyelination of the nerve fibres, with resulting sites of scars. This condition affects the conduction of nerve signals, resulting in motor problems but also in a variety of cognitive symptoms (see 46). The most frequent mental complaint concerns various kinds of memory problems. Cognitive slowing is one general characteristic and another is that executive, working memory functions are impaired (47 – 49). Other cognitive research concerned with the longterm consequences of motor impairment is on cerebral palsy (CP) and hemiphlegia. In the work of Carlsson et al. (50), verbal and non-verbal function data pertinent to the relation between congenital hemiphlegia and cerebral lateralization were collected. Data reveal that especially girls in the righthemiphlegia group are verbally disabled. Since these studies used individuals with non-focal brain damage, it is reasonable to assume that the difference in lateralization is due to disturbance of one or more components in a neural network responsible for language. Both hemiphlegic groups show impairments on visuo-spatial and visuo-constructive tasks. This result, and also later data on dichotic listening and cerebral lateralization, seems to support the notion that girls have a more bilateral language activation. The dichotic listening procedure is widely used. It involves a concurrent presentation of for example syllables. Ear preference indicates which (via contralateral projections) hemisphere is dominant, i.e., suppresses the other (51). Dichotic listening also predicts lateralization, such that right-hemisphere-injured hemiphlegic CP individuals show a right-ear advantage (implicating lefthemisphere dominance), whereas the reverse holds true for left-hemisphere hemiphlegia (52). Forced attention instructions in dichotic listening procedures 40


are assumed to tap subjects’ flexibility to shift attention from one hemisphere to the other (53). This cannot be accomplished for either right-hemisphereinjured or left-hemisphere-injured hemiphlegic individuals. Instead, they stick to the ear that is dominant in the first place, probably suggesting hypo-arousal of the damaged hemisphere (54, 55). In sum, the long-term consequences of motor-impaired children and adults are varied due to the particular neurological condition. But at the same time it is possible to discern that executive functions of a general working memory concept are viable across conditions. Working memory is an active short-term memory system composed of a general executive subsystem and two ‘‘slave’’ systems: the visuo-spatial scratch-pad and the phonological loop (56). PD, ADHD, MS, CAPD, and CP individuals all rely on some deviant central executive function. A cortical-striatal-thalamic-cortical circuit may be common to the first three disorders, albeit in different ways, while the latter two have in common the neuronal circuitry for audioverbal deficits, especially the central components in such a system (57). Audioverbal functions have a general connection to the phonological loop in working memory – a slave system which is supportive of both language production and comprehension. Thus, there are definite cognitive consequences to be expected, which are important for assessment and treatment issues. The consequences are primarily due to either central motor circuits, involving complex interactions between frontal/prefrontal, basal ganglia, thalamic, and frontal neurons, or deficits in networks for audioverbal processing, involving Heschl’s gyrus, the insula, or subcortical regions (57). Interestingly, CAPD individuals seem to be more damaged in the right hemisphere (57), consonant with the stronger right hemisphere involvement in ADHD. The relative deficits in attention may be a general aspect of a limited capacity working memory system that characterizes all five conditions reviewed. Also, if SPT-encoded events are episodically well integrated (39) and motorically well supported (33), they will hence relieve the central executive of some deployment of attentional resources – this is an alternative way of viewing this task in the context of a general working memory system.


Motor activity, memory and language: further consequences While the above examples show a general connection between motor activity and central executive functions and audioverbal functions, there are also more detailed motor-cognitive aspects which represent important consequences for communication. The motor activities represented by the articulatory gestures involved in speech production constitute a fundamental part in working memory. It is generally known that articulatory rehearsal is vital for the phonological loop in working memory. Consequently, speech rate is a sensitive predictor of memory span performance, and use of articulatory suppression and phonological similarity of processed items are effective distractors of span performance (56). So, it is perhaps surprising to learn that non-speaking, dysarthric subjects still evidence phonological similarity effects and normal inner speech (58). The conclusion drawn by Baddeley & Wilson was that peripheral overt speech was not necessary for the development and maintenance of articulatory, central motor programmes (cf. 59). Recent research by Dahlgren Sandberg & Hjelmquist (60) verifies that groups of non-vocal children perform on a par with controls on different phonological awareness tasks (e.g., rhyme recognition and phoneme synthesis). However, reading and spelling were clearly impaired, despite intact phonological abilities – a result clearly at variance with the standard finding that phonemic awareness predicts reading acquisition (e.g., 61). This result could not be ascribed to intellectual level, as a control group of mentally retarded showed better reading and spelling capabilities. However, subsequent analyses of subgroups of reading versus non-reading non-vocal children revealed that the readers evidenced better phonological performance and better short-term memory. This implies that the acquisition of the alphabetic code has a mutually positive influence on the development of skills which are otherwise supported by overt articulation (cf. 62). Working memory applications are plenty. With respect to the phonological loop, areas concerned with reading and learning to read (63), speechreading (5, 16), listening comprehension (64, 65), and learning of foreign vocabularies all testify to its im-


portance in different ways (66). Also, it has recently been shown that phonology is important for deaf children in reading acquisition (67). Motor aspects of sign language are obvious. What is less obvious for the non-user of sign language is that it also depends on phonology – a ‘‘phonology’’ which combines non-sound, sublexical units into meaningful wholes (‘‘words’’) (68). What is even less expected is that sign-language users also show evidence of a phonological loop, much in the same way as for the standard, speech-based model (69). As in the case of dysarthric patients, there is here a need to postulate a more central mechanism which still relies on an inner, abstract loop (70, 71). Thus, a tentative conclusion is that these data tell us that not only is there an independence of ‘‘central’’ phonological representations and the existence of speech codes, there is also an independence as regards what motor activity is involved in producing a particular language. The communicating brain seems to be able to ignore some not always evidently superficial differences in language; instead, language processing is focused on perceiving and combining arbitrary pieces of information to create meaning units (70). Cognitive-motor prerequisites for alternative communication The confluence of information processing in more abstract, modality-free and language neutral networks in the brain reveals possibilities for alternative communicative programmes. For example, aphasic patients, who are impaired in their use and understanding of speech, may use some form of sign language. The notion, then, is that sign language would probe into the functions of a central language processor which is not dependent on speech. Neurophysiological studies show that there are typically high communalities between perceiving speech and sign, and that especially when the speechreader is perceiving audiovisual speech (seeing the speaker, 72) there is evidence that sign and speech activate similar cortical areas (73,74). However, the overlap among cortical activation networks and lateralization depends on factors such as (a) the time period of acquisition of the language; (b) whether the sign-language user is a native language user or not (75, 76); and (c) the skill of the speechreader (71). 41

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In fact, there are more explicit and direct examples supporting the idea that different language input channels tap in to a central, abstract language processor. In one study on the Landau-Kleffner syndrome, it is shown that it is quite possible for an individual to compensate by means of signed English. Here, sign language phonology is intact, as is sign language comprehension. At the same time, spoken language phonology is severely compromised (77). Furthermore, we know that the left frontal operculum (Broca’s area) is typically used during speech production. But, Broca’s area has also been implicated for sign language production. Expressive sign language aphasia was observed in a patient with a left ischaemic infarct in Broca’s area (78). Thus, certain circumstances exist that point in the direction of a central language processor that can be accessed through different language channels. This can provide useful opportunities for compensation for lack of spoken language competence by means of sign language. Still another alternative communication form – predominantly used by profoundly hearing-impaired adults – involves a particular technique of touching voices, viz. tactiling (79). Tactiling means that the subject places his/her palm on the neck, preferably with the thumb on the collar bone, thus complementing visual perception of the speech signal by means of tactile information. This mode of communicating with other individuals can be effective for some, given certain cognitive prerequisites of the perceiver. In fact, there exist only a few very skilled cases in the world. But, on the other hand, they reach speech tracking levels comparable to normal hearing subjects and experience with such persons reveals that they are quite fluent in a dialogue (80). In effect, F0 -information from the speech wave can be picked up by touch, and – when combined with visual information from lip movements – a natural Gestalt is created. The Gestalt builds on the fact that what can be heard in noise represents phonemic information which is hard to lipread – but can be mediated by touch – and, vice versa, what can be extracted from lip movements cannot be heard in noise (81). In the US there is a fairly large bulk of research on speech perception aids in which the tactile sense is used with mechanical (vibrator) stimulation by sin42


gle-channel or multichannel aids (e.g., 82, 83) or electrical stimulation (e.g., 84). Practice effects are well documented, but very dependent on feedback strategies (85). Research in our laboratory on different prototypes for tactilely mediated speech perception reveals that training efficacy is directly dependent on certain cognitive prerequisites of the individual speechreader: speed of phonological judgements (i.e., rhyme judgements) and visual word decoding from lipreading (86). These cognitive prerequisites must be used for screening and rehabilitation purposes and are to some extent generalizable to use of hearing aids (70). Other applications related to touch are the development and use of a vibrator-based sound localization system for the deaf-blind (87). Thus, it may be inferred from the examples above that once we know the cognitive consequences of certain neurological conditions, we may also infer what kinds of cognitive prerequisites are necessary for launching rehabilitation programmes. The examples above from the alternative communication literature reveal several interesting possibilities, as long as the individual is equipped with certain cognitive abilities. A few exceptions to the rule What we have seen in this review is that physiotherapy or physical therapy research is focused on assessments of motor activity and its potential improvement under a large variety of conditions. However, recent exceptions seem promising from the perspective of broadening physiotherapy into the domain of cognition and communication. In one case study of a man with closed head injury, intensive orthopaedic rehabilitation helped motor functions improve in parallel with cognitive functions such as orientation ability, attention and memory. The authors suggest that active physical treatment procedures should be supported even in patients with poor cognitive prognosis (88). Thus, cognitive consequences of the physiotherapeutic treatment were studied as well. In another study (89), communicative intent and use of communicative signals were stimulated in infants with cerebral palsy by means of a co-treatment service provided by a speech-language pathologist and by a physical therapist. The results show that communicative intent improved.


CONCLUDING DISCUSSION The issues I have addressed concern the general link beween motor activity, cognition and communication. This link may be expressed and analysed in different ways. I have chosen to illustrate it via several examples from the neurological and communicative disorders literature, but also from the literature on normal aging. The link can be analysed with motor activity as the criterion variable, i.e., movement retraining, movement relearning and motor improvement are what is measured and focused on. This is the traditional research emphasis in physiotherapy and physical rehabilitation. The potential of cognitive components built in to such remedial and coping programmes, however, is beginning to show in the literature (e.g., 20, 90). The other side of the coin – which is the putative impetus of this article – is to view cognitive and communicative functions as criterion variables, i.e., viewing physical exercises, motor activity, or lack of motor activity (e.g., in the case of certain disabling conditions) not only as something which may affect an individual’s activity but rather as determinants of cognitive function and communication. My general argument in this article is that this flip of the coin – viewing motor activity as an integral part of cognition and communication rather than as separate functions – has implications for the analysis of boundaries and the future direction of physiotherapy research and practice. As has been shown: 1. There is a vast cognitive-communicative literature dealing with (a) short-term, memory consequences of motor activity, (b) long-term cognitive and language consequences of neuro-motor disorders, and (c) motor-cognitive prerequisites for language and communication which – in the future – may prove to play an important role for physiotherapy as a discipline. 2. Compensatory interaction among physical treatment variables and cognitive function is beginning to show in the literature. Here, more explicit cognitive research, e.g., inspired by the SPT-research, may prove to be fruitful. 3. Alternative communication methods based on knowledge about motor activity, language and communication are relatively well researched in the neurocognitive, cognitive and communicative liter-


ature – but the interface between this type of research and physiotherapy research has yet to be made in full. 4. Working memory serves as a good umbrella concept which (a) points to the importance of analysing the negative consequences of many neuro-motor disorders on executive, central functions (e.g., attention) and (b) provides an understanding of the role of phonology, sound-based or non-soundbased, for alternative communication.

ACKNOWLEDGEMENTS The research was supported by a programme grant (0908/1995) to the author from the Swedish Council for Social Research (SFR). Comments by Drs. Stefan Samuelsson and Tomas Karlsson are gratefully acknowledged. REFERENCES* 1. Smyth MM, Morris PE, Levy P, Ellis W. Cognition in action. Hillsdale, N.J.: Lawrence Erlbaum, 1987. 9. von Euler C, Lundberg I, Llina´s R, editors. Basic mechanisms in cognition and language: with special reference to phonological problems in dyslexia. Amsterdam: Elsevier, 1998. 10. Ro¨nnberg J. Cognitive ability and communicative disability. Scand J Psychol 1998;39:125–9. 15. Leybaert J. Phonological representations in deaf children: the importance of early linguistic experience. Scand J Psychol 1998;39:169–73. 16. Lyxell B, Andersson J, Andersson U, Arlinger S, Bredberg G, Harder H. Phonological representation and speech understanding with cochlear implants in deafened adults. Scand J Psychol 1998;39:175–9. 18. Castellanos X. Toward a pathophysiology of attention-deficit/hyperactivity disorder. Clin Pediatr 1997;36:381–93. 20. Swerissen H, Matyas T, Shane T. An experimental investigation of a cognitive-behavioural and movement-retraining program for treatment of chronic pain associated with occupational overuse injuries. Behav Change 1991;8:60–9.

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89. Lloyd GP, Olswang LB. Development of communicative intent in young children with cerebral palsy: a treatment efficacy study. Infant-Toddler Intervention 1995;5:51–69. ADDRESS FOR CORRESPONDENCE:

Jerker Ro¨nnberg Department of Education and Psychology Linko¨ping University SE-581 83 Linko¨ping, Sweden Fax: + 46 13 282145 E-mail: [email protected]