Hans Samuelsson

Anatomical and Neurological Correlates of Acute and Chronic Visuospatial Neglect Following Right Hemisphere Stroke

Anatomical and neurological correlates of visuospatial neglect were studied in 53 patients with a CT-documented right hemisphere stroke. Evidence of neglect at the acute stage poststroke was strongly related to large lesions involving the middle temporal gyrus and/or the temporo-parietal paraventricular white matter. Thus, out of 18 patients with evidence of visuospatial neglect at the acute stage, 12 showed a lesion in the middle temporal gyrus and/or the deep temporo-parietal white matter. Among the 35 patients that failed to show visuospatial neglect, only one patient had a lesion within these areas. Comparing those patients who recovered from neglect with those that did not, a high correlation was found between persisting neglect and a lesion involving the paraventricular white matter in the temporal lobe. On the basis of above findings, it was suggested that a simultaneous damage to the cortico-thalamic system for regulation of arousal and to the neural systems mediating visual orienting, is likely to be followed by persisting neglect symptoms.

Cognitive outcome 10 years after temporal lobe epilepsy surgery: A prospective controlled study

Objective: To explore late effects of temporal lobe resection (TLR) for epilepsy on general cognitive level and memory. Methods: Fifty-one patients who had undergone TLR (23 in the speech-dominant temporal lobe [DTL] and 28 in the nondominant temporal lobe [NDTL]) were assessed preoperatively and 2 and 10 years postoperatively. Twenty-three healthy controls were assessed at baseline and at corresponding intervals. A battery of standardized tests for assessment of general cognitive level and memory was analyzed using a linear mixed model of between-subjects treatment effect and within-subject time effect. Results: The main result was cognitive stability from 2 to 10 years after TLR. The DTL group had declined in verbal memory at the 10-year follow-up compared to the NDTL group and to the controls. However, this decline was detected already 2 years postoperatively, with no further decline from 2 to 10 years. The memory decline was not related to seizure outcome or AED treatment. The NDTL group showed less improvement in performance IQ (PIQ) at the 10-year follow-up compared to the controls. The most important correlate to inferior PIQ scores was continuing seizures, which was more frequent in the NDTL group. Conclusions: In this study, the main finding was cognitive stability from 2 to 10 years after temporal lobe resection. There was no further decline in verbal memory from 2 to 10 years after surgery, lending no support to the notion of an ongoing progressive decline in verbal memory after temporal lobe resection. The verbal memory course was not dependent on seizure outcome or antiepileptic drug treatment.

Verbal memory decline and adverse effects on cognition in adult patients with pharmacoresistant partial epilepsy : a longitudinal controlled study of 36 patients

The aim of this study was to delineate possible longitudinal cognitive changes in adult patients with a long history of pharmacoresistant partial epilepsy. Thirty-six patients and thirty healthy controls were investigated at baseline. A reassessment was conducted, with median test intervals of 4.8 years for the patients and 3.1 years for controls. A standardized battery was used for assessment of general cognitive level and memory. At baseline, patients performed at a significantly lower level on general cognition, immediate recall of pairs of associated words, and retention of learned words and visuospatial stimuli, compared with controls. Analyses of change over time in the patients disclosed significant verbal memory decline in retention of pairs of associated words. Group comparisons of change over time revealed adverse effects in the performance aspect of general cognition on the patients. Also, group comparisons indicated impaired performance across time for the patients in retention of pairs of associated words and retention of visuospatial stimuli. The adverse effect on memory and general cognition in this patient group over the period was clear-cut when compared with the longitudinal changes in an adequate control group.

Serial cognitive change patterns across time after temporal lobe resection for epilepsy

Longitudinal cognitive outcome with respect to general cognitive status and memory at the group and individual levels was studied 10 years after temporal lobe resection for epilepsy. Twenty-five patients who had undergone a medium-term follow-up (T2, median = 2.7 years) also underwent a long-term follow-up (T3, median = 9.8 years). At the group level, there was a significant increment across time, partly due to practice, in IQ (P value from 0.049 to <0.0001) but not in memory variables. On the basis of the normative interval of reassessed matched controls, the analysis at the individual level of change from baseline to T2 disclosed decrements in 12-29% of the patients and increments in 8-21%. These proportions diminished at T3 (0-12 and 0-16%) and the dominating pattern of Performance IQ and verbal memory was a return toward baseline. These findings make the interpretation of an initial (T2) postoperative increment or decrement more problematic and underline the need for a comprehensive evaluation across time, including both at the group and individual levels.

Search pattern in a verbally reported visual scanning test in patients showing spatial neglect.

The present study of right hemisphere stroke patients showed that presence of visuospatial neglect in conventional neglect tests at the postacute stage was strongly associated with an aberrant search pattern in a verbally reported visuo-perceptual scanning test. Compared with normal controls, patients with visuospatial neglect showed a greater proportion of repeated readings of the same target, shorter search sequences, more shifts between horizontal, vertical, and diagonal search, and lower proportion of horizontal search. The relation between spatial neglect and a deficient search pattern was strongly influenced by the asymmetric allocation of attention in the scanning test, with the exception for the proportion of repeated reading which was not influenced by this asymmetry. At follow-up, a significant recovery was noted in the neglect group for the proportion of repeated readings and for the asymmetry in the allocation of attention. However, a high number of omitted targets in the search test was still a common finding in the neglect group and it was suggested that a non-lateralized attentional deficit may have played an important role behind the ineffective search at this point of time.

Different criteria in the assessment of visuospatial neglect.

mg/kg). Endotracheal intubation was performed during muscle relaxation with pancuronium (01 mg/kg). Anaesthesia was maintained with nitrous oxide, oxygen, and isoflurane (0-7-1-2%). Case 1 was a 51 year old man who, since 1986, had had a progressive spastic paraparesis and who complained of cervicobrachial pain. Neuroradiological investigations showed cervical spondylosis with a narrow canal from C3 to C7. The patient underwent a C3-C7 posterior laminectomy. After operation he complained of weakness and paraesthesiae in both hands. Motor and sensory functions in the arms were restored after three to four weeks. Before laminectomy, the potential recorded epidurally at Cv5 after median nerve stimulation was characterised by a normnal P10 followed by an Nil wave with a peak latency of 12-3 ms, and an N13 wave at 13 -9 ms. Amplitude (P1O-N13: 12 X8,pv) and waveform were normal. After laminectomy, the disappearance of the N13 wave was noticed. The P10 and N 1l waves were unchanged (figure). Case 2 was a 56 year old man who presented in 1984 with progressive spastic tetraparesis and hypoaesthesia below C4. An MRI of the cervical spine showed spondylotic stenosis of the canal from C3 to C5. He underwent a C3-C5 posterior laminectomy. After operation, he showed a transient (seven days) decrease of motor performance in the distal segments of the arms. Before laminectomy, the potential evoked by median nerve stimulation at Cv5 consisted of a slightly delayed PlO (peak latency: 11-2 ms), Nl (peak latency: 13-6 ms), N13 (latency: 14-9 ms), followed by a slow positive wave (P18 at 25-8 ms). Amplitude (P10-N13: 15 pv) and waveform were normal. After laminectomy a decreased amplitude (P10-N13: 10-7 pv) and a longer duration (I1-8 ms v a prelaminectomy value of 4 ms duration) of the main negative wave (N13) were evident (figure). Case 3 was a 67 year old man with spastic tetraparesis and hypoaesthesia of both hands. Cervical MRI showed a multisegmental spondylosis from C4 to C7. The patient underwent a C3-C7 posterior laminectomy. After operation a transient (four weeks) increase of the paresis and hypoaesthesia of upper extremities was evident. Before laminectomy, the epidural evoked potentials consisted of a slightly delayed P10 (peak latency 11i3 ms) followed by a negative wave peaking at 14 ms. The amplitude was normal from ThI to Cv6 (P1ON13: 10 ,uv), whereas it was decreased above Cv5-6 (PI0-N13 at Cv5-6: 5 puv). After laminectomy a decrease in amplitude or disappearance of the main negative wave (N13) was evident (figure). In these three cases, laminectomy was followed by an alteration in the postsynaptic component (N13) of the median nerve evoked potential, whereas the root component (NI 1) was unchanged.2 This is consistent with grey matter damage. The genesis of this damage is probably a vascular insult in an already hypoperfused area.34 Indeed, in cervical spondylotic myelopathy the osteophytic process may impinge on the anterior spinal artery and cause hypoperfusion with loss of the haemodynamic autoregulation in the spinal cord watershed areas.5 The decompression by posterior laminectomy may increase the blood supply, but as a consequence of the previously mentioned loss of haemodynamic autoregulation, it may cause hyperaemia in these areas and induce the paradoxal effect of a further ischaemia. Other mechanisms of damage such as cervical spine instability, a local concussion of the cord, or a temporary oedema caused by mechanical interference, cannot be excluded. In conclusion, this neurophysiological study shows that neurological deterioration after posterior laminectomy in these patients was due to grey matter damage and not to nerve root stretching. It is important to stress that the damage reversed spontaneously. B CIONI M MEGLIO L PENTIMALU M VISOCCHI Istituto di Neurochirurgia, Universita Cattolica, Roma, Italy

Visuospatial neglect and an ipsilesional bias during the start of performance in conventional tests of neglect

Abstract This study describes the relationship between an ipsilesional start of performance during conventional tests of neglect and the presence of visuospatial neglect. The validity of using ipsilesional bias as an indicator of neglect was examined in 60 patients with a single right hemisphere stroke, consecutively studied 1-8 weeks and 6-7 months poststroke. The spatial location of the start point within the tests was observed in four subtests from a modified version of the Behavioural Inattention Test. On the basis of defective performance in at least two of the measures used, 83 % of the patients with neglect in the test battery and 98% of the patients with no neglect were correctly identified (Phi = .84). At the follow-up, 50% of the patients with neglect and 98% of the patients with no neglect were correctly identified (Phi = .57). The use of only one measure resulted in a less satisfying outcome because of great variability of performance in the various subtests. It was concluded that a defective ...

Verbal memory decline is less frequent at 10 years than at 2 years after temporal lobe surgery for epilepsy.

We investigated individual short- and long-term verbal memory changes after temporal lobe resection for epilepsy. Fifty-one patients (23 operated on the speech-dominant temporal lobe, DTL and 28 on the non-dominant temporal lobe, NDTL) were tested on learning/immediate recall and delayed recall of word-list and word-pairs preoperatively, 2 years postoperatively and 10years postoperatively. Changes were defined using reliable change indices of 23 healthy controls assessed at corresponding intervals. Fewer patients had reliable declines at 10 years than at 2 years (DTL: 13-35% vs 35-44%; NDTL: 0-4% vs 7-21%). Four DTL patients (17%) had reliable declines in ≥2 tests at 10-year follow-up. More NDTL patients had improvement at 10 years than at 2 years (18-30% vs 4-22%). The only risk factor for decline both short and long term was DTL resection. In conclusion, most patients had stable verbal memory postoperatively. A few DTL patients had a lasting decline at long-term follow-up, but more patients showed partial recovery, especially in the NDTL group.

Psychosocial status 10 years after temporal lobe resection for epilepsy, a longitudinal controlled study

Knowledge about long-term psychosocial outcome of temporal lobe resection (TLR) for epilepsy is limited. The aims of this study were to describe vocational outcome 10 years after TLR and to analyze the effect on the vocational situation by seizures, laterality of resection, verbal memory, and mood. Fifty-one patients were prospectively followed 10 years after TLR. Psychosocial and neuropsychological data were ascertained at baseline and 10 years after surgery and at corresponding time points for 23 controls. Fewer patients worked 10 years post-operatively compared with controls (TLR patients: 61% and controls: 96%). However, seizure-free patients were more likely to retain employment (71%) than patients who had seizures (41%). The odds of working full-time were 9.5 times higher for patients with seizure freedom than for those with continuing seizures. There were no associations between working at 10 years and side of resection or mood, and impairment of verbal memory did not have an influence on vocational outcome.

The prediction of functional dependency by lateralized and non‐lateralized neglect in a large prospective stroke sample

Background and purpose:  Lateralized and non‐lateralized impairments in visual attention have been identified as important components in patients with visuospatial neglect. This study investigated the course of these two phenomena across time in relation to neurological symptoms and functional outcome in a large consecutive and prospective stroke sample.