424 Letters to the Editor gave the correct name of the hospital, he parietal or parieto-temporal cortices are suf- designs, approved by the Local Ethical located it in another city. Despite being ficient to cause it.4 In our patient, right Committee, have been employed: 1) the J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.4.424 on 1 April 1993. Downloaded from repeatedly informed that the hospital was in thalamocapsular damage may have induced time-course of the R2 inhibition was com- Malaga, he denied it and was convinced functional depression of various distant but pared, in the same subject, with that of the that it was a new branch in the city he anatomically connected cortical areas. Data soleus Ia presynaptic inhibition; 2) the named. Although he remained in the same from SPECT, however, revealed secondary effect of intravenous administration of thy- room during his admission to hospital, he cortical deactivation affecting mainly the rotrophin releasing hormone (TRH), a sub- insisted he had been moved daily to identi- right frontal cortex. In this context, we sug- stance shown to increase presynaptic cal hospitals (all with the same name) that gest that functional deactivation of the right inhibition in humans,' has been tested in were located in neighbouring cities cortical mantle, in addition to thalamocap- parallel on both spinal Ia presynaptic inhibi- (Torremolinos, Fuengirola, Marbella). sular injury, may underlie environmental tion and R2 reflex inhibition. In addition, One week after onset, the patient had a reduplication and its associated neuropsy- spinal Ia presynaptic inhibition and trigemi- detailed neuropsychological examination. chological deficits. In addition, given that nal R2 inhibition were studied in a patient He was found to have a WAIS verbal IQ of environmental reduplication probably affected by chronic progressive spino-bulbar 94 and a performance IQ of 51. On the requires preexisting brain pathology (for spasticity, a rare disease presenting with Wechsler Memory Scale (WMS), his mem- example, cortical atrophy) besides the spe- spastic paralysis of facial, laryngeal and ory quotient was normal (99 points); his cific sites of brain damage in the right hemi- lower limb muscles, due to a progressive scores on immediate history recall and asso- sphere,' 2 the presence of leukoaraiosis in and parallel involvement of corticobulbar ciated learning were average though his per- the case by Nighoghossian et al' and in our and cortico-spinal projections.4 Many formance on the visual reproduction subtest own patient might be another risk factor for patients with spasticity show a reduced or was below average. There was no evidence developing it after acute stroke. absent presynaptic inhibition on the soleus MARCELO L BERTHIER Ia primary afferent fibres, probably due to of confabulation in response to items of the Neurology Service, Virgen de la Victoria University Mercer's confabulation battery, but he did Hospital, Mdlaga the loss of a tonic supraspinal excitatory poorly on tests thought sensitive to frontal ANGEL POSADAS drive on interneurons acting presynaptically lobe dysfunction (Wisconsin Card Sorting CARMEN PUENTES on Ia terminals. If inhibition of the R2 Nuclear Medicine Section, Carlos Haya Hospital, Test (categories achieved = 0; normal range Malaga reflex is of presynaptic origin and it is sub- = 4-6), Trail-making test (part A) (below JAIME KULISEVSKY jected to such a descending control, then it percentile 10)). He also showed a severe Neurology Service, Sant Pau Hospital. Autonomous could be expected that a lesion of the cor- impairment on visual-perceptual tests University ofBarcelona, Barcelona, Spain ticobulbar and cortico-spinal projections (Visual Form Discrimination (14 points; would also result in a parallel reduction of normal range 23-32), Facial Recognition presynaptic inhibition on both spinal Ia and (15 points; percentile rank = 1). His lan- Correspondence to: Dr Marcelo L. Berthier, trigeminal primary afferent fibres. Neurology Service, Virgen de la Victoria guage was almost intact, except for a mild University Hospital, Colonia Sta Ines s/n, Figure 1 shows the time-course of pre- visual naming impairment (Boston Naming (29010), Malaga, Spain. synaptic inhibition of the soleus H reflex Test, 38 points (maximum = 60)). in a normal subject. We used a method CT and MRI scans showed a right thala- introduced by Morin, Pierrot-Deseilligny mic haemorrhage with extension into the 1 Nighoghossian N, Trouillas P, Vighetto A, et and Hultborn in 1984,5 which we briefly posterior limb of the internal capsule, coro- al. Spatial delirium following a right subcor- describe. The test response was a soleus H na radiata and ventricular system. Mild tical infarct with frontal deactivation. J reflex evoked by stimulating the posterior Neurol Neurosurg Psychiatry 1992;55:334-5. nerve. symmetrical periventricular white-matter 2 Leiguarda RC. Environmental reduplication tibial To elicit Ia afferent discharge changes compatible with leukoaraiosis were associated with a right thalamic haemor- from pretibial muscles, a short lasting vibra- also observed. Regional cerebral blood flow rhage. J Neurol Neurosurg Psychiatry tion (10 ms; 3 cycles; 300 Hz) was applied 1983;46:1 154. over the tibialis anterior tendon by an elec- was studied with 99Tcm-HMPAO and 3 Pozzilli C, Passafiume D, Bemardi S, et al. SPECT, using an Elscint Apex 609 RG SPECT, MRI and cognitive functions in tromagnetic hammer, 10-400 ms before the gamma camera. Focal blood flows were multiple sclerosis. Jf Neurol Neurosurg test stimulus. Under this experimental con- analysed semiquantitatively in twelve circu- Psychiatry 1991;54:1 10-5. dition, evidence shows that the resulting 4 Patterson MB, Mack JL. Neuropsychological the soleus H lar regions of interest which were placed analysis of a case of reduplicative paramne- long-lasting depression of over the cortical mantle in three successive sia. J Clin Exper Neuropsychology 1985;7: reflex is due solely to presynaptic inhibition 111-21. slices. Asymmetry indices (AI) for each lobe from pretibial Ia afferent fibres to those http://jnnp.bmj.com/ 5 Kapur N, Turner A, King C. Reduplicative mediating the afferent test volley.6 In fig 1 were calculated using the following formula: paramnesia: possible anatomical and neu- (R- L)/(R + L) x 200.3 A marked decrease ropsychological mechanisms. Y Neurol the time-course of the inhibition of the of perfusion was observed in the right thala- Neurosurg Psychiatry 1988;51:579-81. trigemino-facial R2 reflex following a weak mus and basal ganglia as well as in the left conditioning stimulation (0 95 times the cerebellum. Hypoperfusion was also noted perceptive PTh) of the first trigeminal in widespread cortical regions of the right branch is also reported. There is a clear hemisphere affecting mainly the frontal lobe strict similarity of the curves of the R2 and (AI = - 29 6), and to a lesser extent the Evidence for presynaptic inhibition on soleus H reflex inhibition. Identical findings parietal (AI = - 10-8) and temporal (AI = trigeminal primary afferent fibres in have been observed in two other normal on September 23, 2021 by guest. Protected copyright. - 10) lobes (negative AI values indicate left humans subjects. By exploring the upper curve in fig sided hyperactivity relative to the right sided 1 it is apparent that the long-lasting inhibi- activity). In a recent study we have shown that a con- tion of the soleus H reflex is preceded by an The assessment of neuropsychological ditioning electrical stimulus applied to the early short-lasting facilitation (see also the functions in our case of subcortical environ- trigeminal afferent fibres of intensity below upper curve in fig 2). 'This early facilitation mental reduplication revealed more perva- the reflex threshold (Th) (0 90-0 95 times is due to mechanical spread of the vibration sive deficits than those observed in the the perceptive Th) produces unexpected to soleus spindles causing homonymous Ia patient reported by Nighoghossian et al.,' changes of test trigemino-facial reflex facilitation in the soleus motor neurons.6 but similar to those of previous cases show- responses.' In particular, for the R2 This explains why this early facilitation is ing evidence of environmental reduplication response, there is a monotonic depression lacking on the R2 reflex curve (lower curve and cortical involvement. Moreover, the starting at 20-30 ms of interstimulus inter- in fig 1). combination of deficits on nonverbal mem- val, reaching a maximal value at 50-100 ms The histograms on the right in fig 1 show ory, awareness, visual-perceptual skills and and recovering within 300-400 ms (figure the enhancement of the R2 and H reflex reasoning abilities supports the view that 1). Based on the similarity of the depressions after acute intravenous admin- environmental reduplication is a complex, time-courses of the R2 inhibition and of the istration of TRH. It has been demonstrated multifactorial delusional misidentification trigeminal primary afferent depolarisation that a single subcutaneous injection of high- syndrome.4 5 described in the cat,2 we propose that presy- dose TRH (1-2-2-5 mg/Kg) produces dra- Some previous reports emphasised the naptic inhibition from low-Th trigeminal matic and long-lasting (1-2 hours) increase association between environmental redupli- afferent fibres was the primary factor con- of the soleus presynaptic inhibition in cation and the superimposition of bilateral tributing to the depression of the test patients with amyotrophic lateral sclerosis.3 frontal-lobe and right hemisphere cortical response. We describe experimental evi- We have observed a similar but short-last- involvement, while others suggested that dence to support this. ing (10-20 minute) enhancement of the unilateral (right) lesions of either the fronto- Two complementary experimental soleus Ia presynaptic inhibition in normal Letters to the Editor 425

150 T This study was partly carried out at the Istituto di Fisiomedica J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.4.424 on 1 April 1993. Downloaded from TRHI Sokeu H rdlex Loretana, Toro (CB), Italy and sup- 4) ported by a grant from Ministero della Ricerca 125 * Soleus H"refIex 120 Scientifica and Regione Molise, Italy. ALESSANDRO ROSSI lsa 100 A1 CHIARA SCARPINI In Laboratorio di Neurofisiologia, Istituto di Scienze 0 75. 0 80 Neurologiche, Universita di Siena, Italy 60 0 Correspondence to: Professor Rossi, Istituto di 50 0 Scienze Neurologiche, Universita di Siena, Viale at 40 Bracci, 53100 Siena, Italy. 25 20 i~ 1 Rossi A, C. of '4-4 Scarpini Gating trigemino- 0 0 facial reflex from low-threshold trigeminal 50 100 150 200 250 300 350 400 A B C D and extratrigeminal cutaneous fibres in humans. Jf Neurol Neurosurg Psychiatry 'uCd 150i 1992;55:774-80. 9 2 Stewart DH, Scibetta CJ, King RB. Pre- 0 TRH / R2 tuigemno.dcl refe synaptic inhibition in the trigeminal relay 4) 125 t Trlgemino_facial R2 reflex 120 nuclei. J Neurophysiol 1967;20:135-153. 4) 3 Morin C, Pierrot-Deseilligny E. Mecanisme .1 AfUU -I , 100 -LI I spinal de l'action antispastique de la TRH chez les malades atteints de sclerose laterale 0 80 amyotrophique. Rev Neurol 1988;144:701-3. 0 75 -- 0 4 Gastaut JL, Michel B, Figarella-Branger D, 60 4._ Somma-Mauvais H. Chronic Progressive 50-- 0 Spinobulbar Spasticity. Arch Neurol 1988; 00 40 54:509-13. 25- 5 Morin C, Pierrot-Deseilligny E, Hultborn H. 20 Evidence for presynaptic inhibition of mus- cle spindle Ia afferents in man. Neurosci Lett 0 1 2 0- 0i A B C D 1984;44: 137-142. o 50 100 150 200 250 300 350 400 6 Hultborn H, Meunier S, Pierrot-Deseilligny E, Shindo M. Assessing changes in presy- Conditioning-test interval (ms) naptic inhibition of Ia fibres at the onset of voluntary contraction in man. Y Physiol 1987;389:757-72. Figure 1 Left panels. Time-course of the inhibition of the soleus H reflex and tnigemino-facial R2 response. The sizes of the H (peak to peak) and R2 (area) reflexes (as a % of their unconditioned value) are plotted against the time elapsed after the conditioning stimulation oftibialis anterior Ia and trigeminal afferentfibres respectively. Right panels. Unconditioned (Columns A) and conditioned (Columns B) soleus H and trigeminal R2 reflexes obtained before TRH injection Intracranial hypertension following are compared with unconditioned (Columns C) and conditioned (Columns D) reflexes after TRH psittacosis injection. Each column represents the mean of 15 measurements and the vertical bars 1 SE of the mean. All data from the same subject. Neurological complications are rare in psit- tacosis. In 1972 a review of 156 cases reported two with encephalitis and one with subjects after a single acute intravenous 4.9, p < 0-001; t = 6-6, p < 0-001 respec- a lymphocytic meningitis.' Since then there injection of 10 mg of TRH (unpublished tively). As no significant changes of uncon- have been reports of cerebellar disturbance,2 observation). This procedure was therefore ditioned test responses were present sixth nerve palsy,3 and transverse myelitis.4 used in this study. Before and 15 minutes (compare columns A and C) the possibility We report a case of intracranial hyperten- after the end of the injection, 10 uncondi- of some post-synaptic effects on motor sion following psittacosis. tioned and 10 conditioned R2 and H reflex- neurons could be ruled out. Exactly the A 46 year old male was referred with es were randomly evoked. The intensity of same results were obtained in two normal deteriorating vision. He had been well until the conditioning stimuli (applied 100 ms subjects. 10 weeks previously when he developed a before the test ones) was adjusted to elicit, Figure 2 shows the behaviour of the con- severe generalised headache with malaise, in pre-infusion control condition, a small ditioned R2 and H reflexes in a patient with sweats, anorexia, and weight loss. The http://jnnp.bmj.com/ amount of inhibition of both H and R2 chronic progressive spinobulbar spasticity. headache was of gradual onset and associat- reflexes (about 60% of their unconditioned Conditioning stimulation to trigeminal or ed with neck stiffness. There were no respi- values: see columns B). After TRH injec- pretibial Ia fibres failed to produce depres- ratory symptoms. After 8 days of this tion the amount of inhibition of both H and sion of the respective test reflexes. It was illness there was a subacute increase in the R2 reflex responses was significantly also verified in two patients with pure spas- severity of the headache with slurring of increased (columns D) (Student's test: t = tic paraparesis (Strumplell-Lorrain disease, speech and unsteadiness. He was admitted not illustrated) that, despite the absence of to a local hospital where he was noted to 150 the soleus Ia presynaptic inhibition, the have mild neck stiffness. Kemig's was Soleus H rflex sign on September 23, 2021 by guest. Protected copyright. 125 L.0 trigemino-facial R2 response was normally negative and no other neurological signs depressed when preceded by a conditioning were elicited. General examination was nor- discharge of low-Th trigeminal afferent mal. A chest radiograph showed an area of 75- *0 fibres (not illustrated). consolidation in the right lower lobe. A CT Independent observations support the 50-. scan of the brain was normal. CSF exami- ._3 conclusion that presynaptic inhibition on nation was normal with an opening pressure 25-. trigeminal primary afferent fibres is the of 20 5 cm. He was discharged the follow- I main factor contributing to depression of 0 O-- ing day, but the headache persisted for 0 50 100 150 200 250 300 350 40 the R2 response following conditioning acti- another 10 days. There was then an interval -i 150 -. vation of low-Th trigeminal fibres: 1) there of approximately 2 weeks when he was Trgemino-falal R2 eflex is a strict similarity between the time-course asymptomatic and well. Over the following LI 125-- of R2 inhibition and that of trigeminal pri- 6 weeks he noticed gradual loss of vision, 100I * mary afferent depolarisation observed in particularly in the left eye, with some varia- 75< animals; 2) the time-course of R2 inhibition tion but no complete obscurations. He was is identical to the time course of spinal not taking any medication and had not 50 - presynaptic inhibition; 3) TRH, a drug able received any antibiotics during the course of 25-- 0 to increase spinal presynaptic inhibition, is the illness. There was no relevant past med- equally effective in increasing both Ia presy- ical or family history. He was a non-smoker O- 50 100 1 50 200 250 300 350 400 naptic inhibition and the inhibition of the and rarely drank alcohol. He kept ten par- Conditoning-ex interval (mx) trigeminal R2 response; 4) lesion of cortico- rots, one of which had died during the mat- bulbar and cortico-spinal projections results ing season two months before the onset of Figure 2 Patient with chronic spino-bulbar in depression of both spinal presynaptic his illness. The cause of the parrot's death spasticity. As in the left panels in fig 1. inhibition and trigeminal R2 inhibition. was not established.