Phonological short-term memory networks following recovery from Landau and Kleffner syndrome.
Landau-Kleffner syndrome (LKS) is a rare acquired aphasia occurring in otherwise healthy children, together with spike-wave discharges predominating over superior temporal regions and activated by sleep. Although the outcome of language abilities is variable, a residual impairment in verbal short-term memory (STM) is frequent. This STM deficit might be related to the persistent dysfunction of those temporal lobe regions where epileptic discharges were observed during the active phase of the disorder. We tested this hypothesis by measuring brain activation during immediate serial recall of lists of 4 words, compared to single word repetition, using H(2) (15)O positron emission tomography (PET), in 3 LKS patients after recovery and in 14 healthy controls. The patients (TG, JPH, and DC) had shown abnormally increased or decreased glucose metabolism in left or right superior temporal gyrus (STG) at different stages during the active phase of their disease. At the time of this study, the patients were 6-10 years from the active phase of LKS. Results showed that Patients JPH and DC had impaired performance in the STM condition, whereas TG showed near normal performance. PET data showed that JPH and DC activated significantly less than controls left and right posterior STG. TG, having near normal STM performance, showed increased activity in the posterior part of the right STG. These data suggest that impaired verbal STM at late outcome of LKS might indeed be related to a persistent decrease of activity in those posterior superior temporal gyri that were involved in the epileptic focus during the active phase.
Majerus
Steve
S
Department of Cognitive Sciences, University of Liège, Liège, Belgium. smajerus@ulg.ac.be
Laureys
Steven
S
Collette
Fabienne
F
Del Fiore
Guy
G
Degueldre
Christian
C
Luxen
André
A
Van der Linden
Martial
M
Maquet
Pierre
P
Metz-Lutz
Marie-Noëlle
MN
D000161:Acoustic Stimulation; D000328:Adult; D001184:Articulation Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D001931:Brain Mapping; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D018887:Landau-Kleffner Syndrome / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D014055:Tomography, Emission-Computed
D005947:Glucose