Aphonia as the only speech disturbance from bilateral paramedian thalamic infarction L.C. Lazzarino”, and A. Nicolai* Introduction Summary Amnesia and oculomotor disturbances are frequently reported as a consequence of bilateral paramedian thalamic lesions“13. Although less frequent, language disorders after left or bilateral thalamic injury are also describedsJ4-l”. A lowered or fading voice may be present’S~‘7~1H, but has never been described as the only speech disorder. We report a patient with CT documented bilateral paramedian thalamic infarction who presented with transient coma followed by vertical gaze paralysis, mild right hemiparesis, severe amnesia and aphonia without other speech anomalies. Case history A 55-year-old right-handed woman was hospitalized because of abrupt onset of unresponsivness and urinary incontinence. Her past health was good apart from long-standing mild untreated hypertension. On admission pulse was 80 and regular, blood pressure was 180/100; Cheyne-Stokes respiration was also present. She appeared somnolent and passive, but she was able to follow simpel verbal commands and, when prodded, she produced fluent speech without verbal or literal paraphasias. However her speech was scarcely intelligible because of considerable lowering of voice volume. The pupils were small (2 mm) and sluggish. Vertical gaze, in both directions was impossible either on We examined a .%-year-old right-handed woman showing transient coma, amnesia, mild right hemiparesis, vertical gaze impairment and aphonia without aphasia. CT-scanning revealed bilateral paramedian thalamic infarction in the territory of the thaiamo-subthalamic paramedian arteries. Aphonia may occur as a consequence of thalamic lesions, but until now it has not been described as an isolated speech disturbance. Key words: Cerebro-vascular tion, speechdisorder disease, infarc- pursuit or on saccadic movements. Horizontal gaze was normal. The doll’s_head maneuver resulted in vertical deviations which were impossible on volontary efforts. A mild right hemiparesis was noted. Over the next three days the level of consciousness improved and the right hemiparesis cleared; the limitation of the upward gaze decreased. An enhanced high resolution CT scan was performed nine days after admission and showed a low density area involving both paramedian thalami, more extensive on the left side (Fig. 1). Neuropsychological assessments were carried out at 2 weeks and 5 months from the admission. Each examination started with careful1 assessment of attention which was tested by ToulousePierron barrage test, counting backward, digit * Divisione Neurologica Ospedale Civile Gorizia (Italia) Address for correspondence and reprint requests: Aldo Nicolai, Via Eleonora Duse n 22, 34170 Gorizia (Italia) Accepted 11.4.88 C&z Neurrti Neurosurg 198.8. Vol. W-3 265 Table I. Examination of attent~or~ week\ Toulouse-Pierron’s barrage test Time min I6 lh Errorbn 27 ‘I I I J /I llll” c 2.5L’,Ior\ Digit span Forward Backward 5 4 5 1 35 forward ~3 I.5 hackward Counting backward Times s. 20 1 z. I I WC Errors” 3 0 P.S. Fig. 1. Enhanced CT-scan (9 days atter ischaemic involvement of both paramedian more extended on the left side. ~msct) showing thalamic sides. span (Table 1) and by some subtests of spatial exploration and perception (identification of superposed configurations, identifications of colours): the results were almost normal, after allowance for the memory disturbances. Memory impairment evaluated according to the Bisiach’s and ~011.Method for Neuropsychological Evaluation’” showed both anterograde and retrograde memory impairment for serial, associative, and logical modalities, while visual memory was well retained (Table 2). No hemispatial inattention, extinction to double simultaneous stimulations, astereognosis, rightleft disorientation or apraxia were present. Reasoning was normal. On the Wechsler Adult Intelligence Scale only amnesic deficits were detected, the patient reacting within the normal mental range on all but memory subtests. She was aphonic, but the language she was able to whisper was normal on the Boston Diagnostic Aphasia Examination. Five months after the onset, the memory impairment was basically unmodified (Table 2). A marked improvement of vertical gaze paralysis and of voice volume was also noted. 266 = - ..___ Patient’s scores; N.S. = Normal scores. bifurcation and the origin of the posterior communicating artery. Occasionally a common artery from one side may supply both paramedian sides of the thalamus. This variation accounts for the simultaneous occurrence of bilateral infarcts2,2’ that usually cause transient coma followed by neuro-ophthalmologic symptoms, drowsiness, abrupt amnesia’-‘“, dementia and aphasic disturbances’,2,s.7.“. Aphasia from left or bilateral thalamic lesions has been frequently described, although there is uncertainty about its semeiologic characteristics and the role of the dominant thalamus in generating lanA lowered or faded voice is quite guage 2.R~‘3-1y. common as a consequence of thaiamic lesions”.“.lX and appears to reflect an elementary speech disturbance rather than an aphasic disorder”. However, the pathogenesis of this aphonia is not yet known. Gorelick et UP suggest that the anatomic basis for the defect may be the interruption of fibres from the medial globus pallidus and pars reticularis of the substantia nigra, running along the ansa lenticularis Table 2. Neuropsycbological test for memory P s. 2 weeks 5 months Verbal - 1) Recall of lo&al stories Leamin of 3 series of words ( J 0) 5 8 13 8 h 0 I? K h.X8+1J.s ll.Mi1.12 ix 2451 17 14.2+4.h 7 7 ,%I,?xi good !Jd Lrood good Vrsual memory P.S.: NS memory Digrt span (see Table Discussion The paramedian thalamic areas are supplied by perforating branches (anterior thalamo-subthalamic paramedian arteries) arising from the posterior cerebral arteries between the basilar , month\ Recall of configurations after 2 min. Memory for faces Pat~ent’s Scores. N.S.: Normal Scares h and carrying extrapyramidal imputs to VA and rostra1 portion of VL nucleus of the thalamus. Conventional CT, in which 10 mm slices are used, has only a limited capacity to localize the specific nuclei affected13. 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