Schweregrad und Rückbildung von Aphasien: Darstellung mittels funktioneller Bildgebung[1]

Zusammenfassung

Die Lokalisation sowie das Ausmaß einer fokalen Hirnläsion bestimmen das funktionelle Defizit. Die Wiederherstellung der betroffenen Funktion hingegen hängt in 1. Linie von der Plastizität der intakten Hirnrindenanteile ab. Die Bedeutung bestimmter Regionen im funktionellen Sprachnetzwerk kann mittels funktioneller bildgebender Verfahren dargestellt werden. Darüber hinaus kann der Effekt von Schädigungen spezifischer Kortexareale aufgezeigt werden. Im Rahmen solcher Untersuchungen bei Aphasikern wurden verschiedene Veränderungen des funktionellen Aktivierungsmusters bestimmten Sprachstörungen zugeordnet. Bei Patienten mit Aphasie durch einen ischämischen Hirninfarkt oder andere umschriebene Läsionen (z. B. Hirntumore) ist der Erhalt oder die funktionelle Reintegration des Gyrus temporalis superior (STG) entscheidend für eine zufriedenstellende klinische Erholung. Die Reaktivierung anderer ipsilateraler Sprachzentren oder kontralateraler Regionen fand sich bei Patienten mit geringerer Besserung ohne zufriedenstellende Sprachproduktion.

Abstract

Activation patterns in functional networks of the central nervous system can be studied with functional imaging modalities, e. g., positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). If disturbances of neurologic function occur, these activation patterns are altered. Language is based on the interplay of a distributed network in which partial functions are executed in various centers, the primary language areas. The organization of these areas is hierarchical, lateralized to the dominant (usually left) hemisphere and adapts to the complexity of the specific language tasks. The specialization of different centers and the lateralization of functions are achieved by collateral and transcallosal inhibition of secondary language areas that are, under normal circumstances, not used for language performance. The interaction between primary and secondary language areas is of particular importance for the recovery from post-stroke aphasia. Functional imaging studies have demonstrated that aphasic patients with a favorable recovery predominantly activate areas in the dominant hemisphere during speech tasks. On the contrary, activation within the non-dominant (usually right) hemisphere might be a marker of failed or faulty recovery attempts or the breakdown of a balanced interhemispheric inhibition. Studies utilizing a combination of repetitive transcranial magnetic stimulation (rTMS) with functional imaging suggest a less effective compensatory potential of non-dominant network areas. Therefore, (over-)activation of non-dominant language areas may represent a maladaptive strategy by paradoxical functional facilitation as a result of decreased interhemispheric inhibition. Suppression of this paradoxical activation, e. g. with rTMS, might therefore be useful as a complementary therapy of aphasia.

Schlüsselwörter

Aktivierungsstudien - Aphasie - funktionelle Bildgebung - transkranielle Magnetstimulation - Schlaganfall

Key words

activation studies - aphasia - functional neuroimaging - language recovery - transcranial magnetic stimulation - stroke

1 WSO Leadership in Stroke Medicine Award Lecture, Wien, 26.9.2008.

• 1 Petersen SE. et al . Positron emission tomographic studies of the cortical anatomy of single-word processing.  Nature. 1988;  331 585-589
• 2 Price CJ. The anatomy of language: contributions from functional neuroimaging.  J Anat. 2000;  197 (Pt 3) 335-359
• 3 Heiss WD. et al . Differential capacity of left and right hemispheric areas for compensation of poststroke aphasia.  Ann Neurol. 1999;  45 430-438
• 4 Wise RJ. Language systems in normal and aphasic human subjects: functional imaging studies and inferences from animal studies.  Br Med Bull. 2003;  65 95-119
• 5 Basso A. et al . The role of the right hemisphere in recovery from aphasia. Two case studies.  Cortex. 1989;  25 555-566
• 6 Cao Y. et al . Cortical language activation in stroke patients recovering from aphasia with functional MRI.  Stroke. 1999;  30 2331-2340
• 7 Gainotti G. The riddle of the right hemisphere's contribution to the recovery of language.  Eur J Disord Commun. 1993;  28 227-246
• 8 Weiller C. et al . Recovery from Wernicke's aphasia: a positron emission tomographic study.  Ann Neurol. 1995;  37 723-732
• 9 Sokoloff L. Energetics of functional activation in neural tissues.  Neurochem Res. 1999;  24 321-329
• 10 Laughlin SB, Attwell D. The metabolic cost of neural information: from fly eye to mammalian cortex.  HFSP Workshop 11 – Neuroenergetics. 2001;  54-64
• 11 Magistretti PJ. Brain energy metabolism. In From Molecules to Networks, Byrne JH, Roberts JL, Editors. Amsterdam: Elsevier Academic Press; 2004: 67-90
• 12 Reivich M. et al . The [18F] fluorodeoxyglucose method for the measurement of local cerebral glucose utilization in man.  Circ Res. 1979;  44 127-137
• 13 Mintun MA. et al . Blood flow and oxygen delivery to human brain during functional activity: theoretical modeling and experimental data.  Proc Natl Acad Sci USA. 2001;  98 6859-6864
• 14 Ogawa S. et al . Brain magnetic resonance imaging with contrast dependent on blood oxygenation.  Proc Natl Acad Sci USA. 1990;  87 9868-9872
• 15 Karbe H. et al . Brain plasticity in poststroke aphasia: what is the contribution of the right hemisphere?.  Brain Lang. 1998;  64 215-230
• 16 Nudo RJ. et al . Neural substrates for the effects of rehabilitative training on motor recovery after ischemic infarct.  Science. 1996;  272 1791-1794
• 17 Heiss WD, Thiel A. A proposed regional hierarchy in recovery of post-stroke aphasia.  Brain Lang. 2006;  98 118-123
• 18 Knecht S. et al . Degree of language lateralization determines susceptibility to unilateral brain lesions.  Nat Neurosci. 2002;  5 695-699
• 19 Thiel A. et al . Localization of language-related cortex with 15O-labeled water PET in patients with gliomas.  Neuroimage. 1998;  7 284-295
• 20 Hickok G, Poeppel D. The cortical organization of speech processing.  Nat Rev Neurosci. 2007;  8 393-402
• 21 Demonet JF. et al . PET Studies of Phonological Processing: A Critical Reply to Poeppel.  Brain Lang. 1996;  55 352-379
• 22 Booth JR. et al . The role of the basal ganglia and cerebellum in language processing.  Brain Res. 2007;  1133 136-144
• 23 Wade DT. et al . Aphasia after stroke: natural history and associated deficits.  J Neurol Neurosurg Psychiatry. 1986;  49 11-16
• 24 Cappa SF. et al . A PET follow-up study of recovery after stroke in acute aphasics.  Brain Lang. 1997;  56 55-67
• 25 Feeney DM, Baron JC. Diaschisis.  Stroke. 1986;  17 817-830
• 26 Karbe H. et al . Regional metabolic correlates of Token test results in cortical and subcortical left hemispheric infarction.  Neurology. 1989;  39 1083-1088
• 27 Metter EJ. et al . Temporoparietal cortex in aphasia. Evidence from positron emission tomography.  Arch Neurol. 1990;  47 1235-1238
• 28 Metter EJ. et al . Subcortical structures in aphasia. An analysis based on (F-18)-fluorodeoxyglucose, positron emission tomography, and computed tomography.  Arch Neurol. 1988;  45 1229-1234
• 29 Kumar R, Masih AK, Pardo J. Global aphasia due to thalamic hemorrhage: a case report and review of the literature.  Arch Phys Med Rehabil. 1996;  77 1312-1315
• 30 Karbe H. et al . Long-term prognosis of poststroke aphasia studied with positron emission tomography.  Arch Neurol. 1995;  52 186-190
• 31 Heiss WD, Emunds HG, Herholz K. Cerebral glucose metabolism as a predictor of rehabilitation after ischemic stroke.  Stroke. 1993;  24 1784-1788
• 32 Metter EJ. et al . Cerebellar glucose metabolism in chronic aphasia.  Neurology. 1987;  37 1599-1606
• 33 Hillis AE. et al . Restoring cerebral blood flow reveals neural regions critical for naming.  J Neurosci. 2006;  26 8069-8073
• 34 Rosen HJ. et al . Neural correlates of recovery from aphasia after damage to left inferior frontal cortex.  Neurology. 2000;  55 1883-1894
• 35 Ohyama M. et al . Role of the nondominant hemisphere and undamaged area during word repetition in poststroke aphasics. A PET activation study.  Stroke. 1996;  27 897-903
• 36 Price CJ, Crinion J. The latest on functional imaging studies of aphasic stroke.  Curr Opin Neurol. 2005;  18 429-434
• 37 Saur D. et al . Dynamics of language reorganization after stroke.  Brain. 2006;  129 (Pt 6) 1371-1384
• 38 Raboyeau G. et al . Right hemisphere activation in recovery from aphasia: lesion effect or function recruitment?.  Neurology. 2008;  70 290-298
• 39 Musso M. et al . Training-induced brain plasticity in aphasia.  Brain. 1999;  122 (Pt 9) 1781-1790
• 40 Naeser MA. et al . Overt propositional speech in chronic nonfluent aphasia studied with the dynamic susceptibility contrast fMRI method.  Neuroimage. 2004;  22 29-41
• 41 Berthier ML. et al . Transcortical aphasia. Importance of the nonspeech dominant hemisphere in language repetition.  Brain. 1991;  114 (Pt 3) 1409-1427
• 42 Fernandez B. et al . Functional MRI follow-up study of language processes in healthy subjects and during recovery in a case of aphasia.  Stroke. 2004;  35 2171-2176
• 43 Belin P. et al . Recovery from nonfluent aphasia after melodic intonation therapy: a PET study.  Neurology. 1996;  47 1504-1511
• 44 Warburton E. et al . Mechanisms of recovery from aphasia: evidence from positron emission tomography studies.  J Neurol Neurosurg Psychiatry. 1999;  66 155-161
• 45 Ferro JM, Mariano G, Madureira S. Recovery from aphasia and neglect.  Cerebrovasc Dis. 1999;  9 (S 05) 6-22
• 46 Greener J, Enderby P, Whurr R. Pharmacological treatment for aphasia following stroke.  Cochrane Database Syst Rev. 2001;  CD000424
• 47 Walker-Batson D. et al . A double-blind, placebo-controlled study of the use of amphetamine in the treatment of aphasia.  Stroke. 2001;  32 2093-2098
• 48 Berthier ML. et al . A randomized, placebo-controlled study of donepezil in poststroke aphasia.  Neurology. 2006;  67 1687-1689
• 49 Orgogozo JM. Piracetam in the treatment of acute stroke.  Pharmacopsychiatry. 1999;  32 (S 01) 25-32
• 50 Kessler J. et al . Piracetam improves activated blood flow and facilitates rehabilitation of poststroke aphasic patients.  Stroke. 2000;  31 2112-2116
• 51 Crinion JT, Leff AP. Recovery and treatment of aphasia after stroke: functional imaging studies.  Curr Opin Neurol. 2007;  20 667-673
• 52 Pascual-Leone A. et al .Handbook of Transcranial Magnetic Stimulation. London: Arnold Press; 2002
• 53 Thiel A. et al . Direct demonstration of transcallosal disinhibition in language networks.  J Cereb Blood Flow Metab. 2006;  26 1122-1127
• 54 Siebner HR. et al . Continuous transcranial magnetic stimulation during positron emission tomography: a suitable tool for imaging regional excitability of the human cortex.  Neuroimage. 2001;  14 883-890
• 55 Winhuisen L. et al . Role of the contralateral inferior frontal gyrus in recovery of language function in poststroke aphasia: a combined repetitive transcranial magnetic stimulation and positron emission tomography study.  Stroke. 2005;  36 1759-1763
• 56 Thiel A. et al . From the left to the right: How the brain compensates progressive loss of language function.  Brain Lang. 2006;  98 57-65
• 57 Zahn R, Schwarz M, Huber W. Functional activation studies of word processing in the recovery from aphasia.  J Physiol Paris. 2006;  99 370-385
• 58 Naeser MA. et al . Improved picture naming in chronic aphasia after TMS to part of right Broca's area: an open-protocol study.  Brain Lang. 2005;  93 95-105
• 59 Ridding MC, Rothwell JC. Is there a future for therapeutic use of transcranial magnetic stimulation? Nat Rev Neurosci. 2007;  8 559-567

1 WSO Leadership in Stroke Medicine Award Lecture, Wien, 26.9.2008.

Korrespondenzadresse