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The neuropsychology of epilepsy: what are the factors involved?
Epilepsy & Behavior Epilepsy & Behavior 5 (2004) S1–S2 www.elsevier.com/locate/yebeh
Introduction
The neuropsychology of epilepsy: what are the factors involved? Albert P. Aldenkamp,a,b,* Gus A. Baker,c and Kimford J. Meadord a
Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Heeze, The Netherlands Department of Neurology, University Hospital of Maastricht, Maastricht, The Netherlands c University Department of Neurosciences, Liverpool, UK d Department of Neurology, Georgetown University Hospital, Washington, DC, USA
b
Received 4 November 2003; accepted 4 November 2003
The consequences of epilepsy are often as serious as having the disorder itself. One particularly important consequence is the impairment of cognitive function [1]. The enormous body of research that has been carried out over a period of more than a century (the studies by Reynolds in 1861 and Gowers in 1885 are generally considered an important starting point) contains ample evidence to illustrate that people with epilepsy, as a group, have serious cognitive problems [2]. Sometimes, individual patients find these cognitive consequences more debilitating than the actual seizures. Cognitive function may be defined as the capacity of the brain to process information accurately and to program adaptive behavior. It involves the ability to solve problems, communicate, memorize information, or focus attention [3]. Epilepsy is a symptom of ictal and interictal brain dysfunction. The underlying etiology and the treatment of epilepsy may also affect cognition. Hence, it seems obvious that cognitive impairment develops as a symptom secondary to the epilepsy. Cognitive impairment is here defined on a clinical basis, as a nonprogressive state to differentiate it from dementia. Most types of cognitive impairment in epilepsy fall within the DSM-IV category of MNCD, Mild Neurocognitive Disorder. A considerable body of research exists with regard to the type of cognitive impairment in epilepsy. Slowing on speeded tasks, involving tasks that require complex information processing (‘‘mental slowing’’), memory impairment, and attentional and concentration difficulties are the most frequent disorders associated with epilepsy [4,5]. * Corresponding author. Present address: P.O. Box: 61, NL-5590 A.B. Heeze, The Netherlands. Fax: +31-40-2260426. E-mail addresses: [email protected], B.Aldenkamp@ Neurolog.unimaas.nl (A.P. Aldenkamp).
1525-5050/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2003.11.001
Although the exact cause of cognitive impairment in epilepsy has not been fully explored, it is clear that three factors are involved: etiology, the seizures, and the ‘‘central’’ side effects of treatment [6]. When evaluating these factors, clinicians must realize that, in practice, most cognitive problems have a multifactorial origin and that the three aforementioned factors, combined, are responsible for the ‘‘makeup’’ of cognitive problems in the majority of patients. Moreover, these three factors are related. This can cause therapeutic dilemmas when seizure control can be achieved only with treatments that are associated with cognitive side effects. Nonetheless, these factors are discussed here separately and sequentially. The overall impact of these factors is also highlighted. In 1999 the same editors reviewed this topic using a similar approach [7]. This publication uses new insights and a broader faculty. In the first section the effect of etiology is covered by Besag (children) and Jockeit and Schacher (adults). In the second section the effect of seizures is covered by Dodrill. An article on the effect of paroxysmal epileptic activity by Aldenkamp and Arends and an article summarizing the evidence from animal experiments by Majak and Pitkanen follow. The third section reviews the effects of treatment: epilepsy surgery (Helmstaedter), vagus nerve stimulation (Schachter), and the side effects of antiepileptic drug treatment on cognition (Ortinsky and Meador) and on mood (Reijs, Aldenkamp, and De Krom). Moreover, as the focus of this supplement is on clinical issues we have added a fourth section. Clinical neuropsychology in epilepsy is involved mainly in the diagnosis of cognitive impairment, the assessment of the impact of cognitive dysfunction on daily life and quality of life, and the rehabilitation of individual patients using for example function training programs such as memory training [8,9]. We therefore add some clinical issues of
S2
A.P. Aldenkamp et al. / Epilepsy & Behavior 5 (2004) S1–S2
diagnosis (Baker and Goldstein). Finally, a research topic was included. MRI has changed neurology and now also influences neuropsychology [10]. This is particularly the case for the use of functional MRI, which allows us to couple behavioral assessment with imaging. The lessons derived from fMRI for the neuropsychology of epilepsy are covered by Vingerhoets and co-workers.
References [1] Aldenkamp AP, Dreifuss FE, Renier WO. Epilepsy in children and adolescents. New York: CRC Press; 1995. [2] Pellock JM, Dodson WE, Bourgeois BFD. Pediatric epilepsy: diagnosis and therapy. 2nd ed. New York: Demos; 2001. [3] Rapin I. Children with brain dysfunction; neurology, cognition, language and behavior. New York: Raven Press; 1982. [4] Prevey ML, Delaney RC, Cramer JA, Mattson RH for VA Epilepsy Comparative Study 264 Group. Complex partial and secondarily generalized seizure patients: cognitive functioning
[5]
[6] [7]
[8]
[9]
[10]
prior to treatment with antiepileptic medication. Epilepsy Res 1998;30:1–9. Jokeit H, Ebner A. Long term effects of refractory temporal lobe epilepsy on cognitive abilities: a cross sectional study. J Neurol Neurosurg Psychiatry 1999;67:44–50. Bourgeois BFD, Presky AL, Palkes HS. Intelligence in epilepsy: a prospective study in children. Ann Neurol 1983;14:438–44. Aldenkamp AP, Baker G, Dodrill C, Meador KJ. Factors affecting cognitive function in epilepsy. Publication on the EUCARE internet site: http://diseaseManagement.ucb.be. 1999. Aldenkamp AP. Clinical neuropsychology: cognitive function in epilepsy. In: Brodie M et al., editors. European white paper on epilepsy. Brussels: EUCARE, UCB, S.A.; 2001. Aldenkamp AP, Hendriks M. Managing cognitive and behavioural consequences of epilepsy. In: Baker GA, Jacoby A, editors. Quality of life in epilepsy. Amsterdam: Harwood Academic; 2000. p. 12–31. Cuenod CA, Bookheimer SY, Hertz-Pannier L, et al. Functional MRI during word generation, using conventional equipment: a potential tool for language localization in the clinical environment. Neurology 1995;45:1821–7.
Introduction
The neuropsychology of epilepsy: what are the factors involved? Albert P. Aldenkamp,a,b,* Gus A. Baker,c and Kimford J. Meadord a
Department of Behavioral Sciences, Epilepsy Center Kempenhaeghe, Heeze, The Netherlands Department of Neurology, University Hospital of Maastricht, Maastricht, The Netherlands c University Department of Neurosciences, Liverpool, UK d Department of Neurology, Georgetown University Hospital, Washington, DC, USA
b
Received 4 November 2003; accepted 4 November 2003
The consequences of epilepsy are often as serious as having the disorder itself. One particularly important consequence is the impairment of cognitive function [1]. The enormous body of research that has been carried out over a period of more than a century (the studies by Reynolds in 1861 and Gowers in 1885 are generally considered an important starting point) contains ample evidence to illustrate that people with epilepsy, as a group, have serious cognitive problems [2]. Sometimes, individual patients find these cognitive consequences more debilitating than the actual seizures. Cognitive function may be defined as the capacity of the brain to process information accurately and to program adaptive behavior. It involves the ability to solve problems, communicate, memorize information, or focus attention [3]. Epilepsy is a symptom of ictal and interictal brain dysfunction. The underlying etiology and the treatment of epilepsy may also affect cognition. Hence, it seems obvious that cognitive impairment develops as a symptom secondary to the epilepsy. Cognitive impairment is here defined on a clinical basis, as a nonprogressive state to differentiate it from dementia. Most types of cognitive impairment in epilepsy fall within the DSM-IV category of MNCD, Mild Neurocognitive Disorder. A considerable body of research exists with regard to the type of cognitive impairment in epilepsy. Slowing on speeded tasks, involving tasks that require complex information processing (‘‘mental slowing’’), memory impairment, and attentional and concentration difficulties are the most frequent disorders associated with epilepsy [4,5]. * Corresponding author. Present address: P.O. Box: 61, NL-5590 A.B. Heeze, The Netherlands. Fax: +31-40-2260426. E-mail addresses: [email protected], B.Aldenkamp@ Neurolog.unimaas.nl (A.P. Aldenkamp).
1525-5050/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2003.11.001
Although the exact cause of cognitive impairment in epilepsy has not been fully explored, it is clear that three factors are involved: etiology, the seizures, and the ‘‘central’’ side effects of treatment [6]. When evaluating these factors, clinicians must realize that, in practice, most cognitive problems have a multifactorial origin and that the three aforementioned factors, combined, are responsible for the ‘‘makeup’’ of cognitive problems in the majority of patients. Moreover, these three factors are related. This can cause therapeutic dilemmas when seizure control can be achieved only with treatments that are associated with cognitive side effects. Nonetheless, these factors are discussed here separately and sequentially. The overall impact of these factors is also highlighted. In 1999 the same editors reviewed this topic using a similar approach [7]. This publication uses new insights and a broader faculty. In the first section the effect of etiology is covered by Besag (children) and Jockeit and Schacher (adults). In the second section the effect of seizures is covered by Dodrill. An article on the effect of paroxysmal epileptic activity by Aldenkamp and Arends and an article summarizing the evidence from animal experiments by Majak and Pitkanen follow. The third section reviews the effects of treatment: epilepsy surgery (Helmstaedter), vagus nerve stimulation (Schachter), and the side effects of antiepileptic drug treatment on cognition (Ortinsky and Meador) and on mood (Reijs, Aldenkamp, and De Krom). Moreover, as the focus of this supplement is on clinical issues we have added a fourth section. Clinical neuropsychology in epilepsy is involved mainly in the diagnosis of cognitive impairment, the assessment of the impact of cognitive dysfunction on daily life and quality of life, and the rehabilitation of individual patients using for example function training programs such as memory training [8,9]. We therefore add some clinical issues of
S2
A.P. Aldenkamp et al. / Epilepsy & Behavior 5 (2004) S1–S2
diagnosis (Baker and Goldstein). Finally, a research topic was included. MRI has changed neurology and now also influences neuropsychology [10]. This is particularly the case for the use of functional MRI, which allows us to couple behavioral assessment with imaging. The lessons derived from fMRI for the neuropsychology of epilepsy are covered by Vingerhoets and co-workers.
References [1] Aldenkamp AP, Dreifuss FE, Renier WO. Epilepsy in children and adolescents. New York: CRC Press; 1995. [2] Pellock JM, Dodson WE, Bourgeois BFD. Pediatric epilepsy: diagnosis and therapy. 2nd ed. New York: Demos; 2001. [3] Rapin I. Children with brain dysfunction; neurology, cognition, language and behavior. New York: Raven Press; 1982. [4] Prevey ML, Delaney RC, Cramer JA, Mattson RH for VA Epilepsy Comparative Study 264 Group. Complex partial and secondarily generalized seizure patients: cognitive functioning
[5]
[6] [7]
[8]
[9]
[10]
prior to treatment with antiepileptic medication. Epilepsy Res 1998;30:1–9. Jokeit H, Ebner A. Long term effects of refractory temporal lobe epilepsy on cognitive abilities: a cross sectional study. J Neurol Neurosurg Psychiatry 1999;67:44–50. Bourgeois BFD, Presky AL, Palkes HS. Intelligence in epilepsy: a prospective study in children. Ann Neurol 1983;14:438–44. Aldenkamp AP, Baker G, Dodrill C, Meador KJ. Factors affecting cognitive function in epilepsy. Publication on the EUCARE internet site: http://diseaseManagement.ucb.be. 1999. Aldenkamp AP. Clinical neuropsychology: cognitive function in epilepsy. In: Brodie M et al., editors. European white paper on epilepsy. Brussels: EUCARE, UCB, S.A.; 2001. Aldenkamp AP, Hendriks M. Managing cognitive and behavioural consequences of epilepsy. In: Baker GA, Jacoby A, editors. Quality of life in epilepsy. Amsterdam: Harwood Academic; 2000. p. 12–31. Cuenod CA, Bookheimer SY, Hertz-Pannier L, et al. Functional MRI during word generation, using conventional equipment: a potential tool for language localization in the clinical environment. Neurology 1995;45:1821–7.