The Influence of Side and Order of Injection on Memory and Motor Power During the Intracarotid Amobarbital Test (IAT)
Abstract number :
2.258
Submission category :
Year :
2000
Submission ID :
3255
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Thomas Bengner, Martin Merschhemke, Martina Sanders, Heinz Haettig, Heinz J Meencke, Uta Pertschy, Thomas Albrecht, Epilepsy Ctr Berlin, KEH, Berlin, Germany; KEH, Radiology, Berlin, Germany.
RATIONALE: To evaluate the influence of injection side (left vs. right), order of injection (first vs. second) and congruence between side of planned resection and first injection (congruent vs. incongruent) on recognition-memory and regain of motor power. METHODS: 34 epilepsy patients performed bilateral IAT as part of a presurgical monitoring program (patients with any signs of obtundation or large morphological lesions were excluded). 28 patients had left- hemisphere speech dominance, 6 were bilateral. In most patients 125 mg Amytal Sodium, solved in 10mL sterile water, was injected with a speed of 2mL/sec. Time between injections was 30 to 35 minutes. In 22 patients the first injection was administered to the side of the planned resection, in 12 patients to the contralateral hemisphere. Recognition items included real objects, drawings, words and sentences. RESULTS: The left-hemisphere dominant patients showed longer lasting regain of contralateral motor power and worsened recognition after left than right injection (p<.01). Analysing exclusively the recognition of real objects revealed the same result (p<.05). Patients with bilateral speech (N=6) showed no differences in a) recognition and b) regain of motor power, between left and right injection (a: p>.90; b: p>.35). Recognition was worse after the second than after the first injection (N=34; p<.01) while regain of motor power did not take significantly longer (p>.10). Whether the first injection was incongruent (N=12) or congruent (N=22) had no impact on recognition after the first injection (p>.50). After the second injection the congruent group got worse while the incongruent group did not (p<.05). There were no comparable significant effects between the two groups concerning regain of motor power. CONCLUSIONS: Worsened recognition and longer lasting regain of motor power after left hemisphere injection in left-hemisphere dominant patients questions the validity of a clinical judgement on memory lateralisation. Worsened recognition after the second injection might be avoided by a first injection into the hemisphere contralateral to the planned side of resection.